AudioNervosa

Self Medicating => General DIY => Topic started by: richidoo on April 19, 2011, 10:17:39 AM

Title: DTQWT-12
Post by: richidoo on April 19, 2011, 10:17:39 AM
Designed by Troels Gravesen in Denmark.

http://www.troelsgravesen.dk/DTQWT-12.htm

(http://www.troelsgravesen.dk/DTQWT-12_Ferraioli_files/DTQWT-12_1.jpg)

95dB, 8 ohms, full range, passive crossover, horn loaded 3 way

Drivers:
Audax 1.2" silk dome tweeter with wave guide
Custom uncoated paper midrange designed by Gravesen, made by SEAS with foam surround
Eminence Deltalite 2512 woofers (2 per speaker, on rear baffle)

The bass drivers will fit in my previous E-Lips OB baffle as will the upper drivers, using an active crossover.

I bought the kit from Jantzen about 2 months ago, with the crossover parts, tweeter and midrange drivers. I procrastinated on buying the woofers, but after Axpona I got psyched up to get started. The Eminence drivers I had sitting in my partsexpress cart were gone. A huge 85% price increase when I tried to put them back in. Neodymium magnets and copper coils are skyrocketing. Same price hike at USspeakers.com. Google shopping found plenty of them still marked at the old price.  :thumb: I might buy 4 of the 10" and 2 of the 15" while I still can, for future iterations of this design.

Now I need to pick up the plywood and draw a cutting plan.

I'm really looking forward to hearing these. There is a smaller version with 10" bass drivers which a couple dozen people have built and commented favorably on the sound. Only one other guy in Italy has built these big ones. But what can I say, I like big bass and I cannot lie.

Not sure about how to finish them. Veneer would be nice, but I don't think I want to sink another $500 into it. These boxes are huge 1' x 2' x 5'. So I will probably use contact paper or paint. Dunno yet.

I bought my Manley 300Bs 2 years ago destined for these Troels speakers. Finally getting around to it. Can I do it in one month?
Rich
Title: Re: DTQWT-12
Post by: rollo on April 19, 2011, 12:02:25 PM
  Now that sounds like something to love. 300Bs and those could just put you over the top. Wow1


charles
Title: Re: DTQWT-12
Post by: richidoo on April 19, 2011, 12:42:27 PM
Time will tell Charlie. It could suck. Only one other person has ever heard it, and he's not said much since his first impressions. But by my calculations it should be at least OK. Enough to get me down the road to where I can buy something better. I won't sell the 300Bs until I use them for the reason I bought them. They can make 24W in PP, so should be enough to boogie with twin 99dB woofers in a 10 foot long horn. We'll see. Keeps me out of jail.

I found a place for pro woodworkers to buy veneer in quantity. No more Rockler $10 /sq ft.
http://www.glveneer.com/index.html
Long way to go before that decision.
Title: Re: DTQWT-12
Post by: tmazz on April 19, 2011, 12:48:43 PM
Time will tell Charlie. It could suck. Only one other person has ever heard it, and he's not said much since his first impressions. But by my calculations it should be at least OK. Enough to get me down the road to where I can buy something better. I won't sell the 300Bs until I use them for the reason I bought them. They can make 24W in PP, so should be enough to boogie with twin 99dB woofers in a 10 foot long horn. We'll see. Keeps me out of jail.

I found a place for pro woodworkers to buy veneer in quantity. No more Rockler $10 /sq ft.
http://www.glveneer.com/index.html
Long way to go before that decision.

Look out, the sawdust is flying again!  :D
Title: Re: DTQWT-12
Post by: evan1 on April 19, 2011, 12:49:37 PM
Can't wait to see how it turns out. Now get to work.
Title: Re: DTQWT-12
Post by: stereofool on April 19, 2011, 06:12:11 PM
Finally getting around to it. Can I do it in one month?
Rich

Get with it, boy  :pop !!!

You've got to finish this project before you can think seriously about those Legacy's  :rofl:.
Title: Re: DTQWT-12
Post by: richidoo on April 19, 2011, 06:23:46 PM
Hey Steve, You should have been a poker player - You can read minds.

More like I need to sell these before I can afford Legacys!!  :rofl:

I'm hoping I will like them better than Legacys. What are the odds of that?? 1:100  But the violins will sound nice... Hopefully not too nice.

I laid out the cutting plan. I will need six sheets of 4x8 for the pair, with 2 sheets of waste. Pisser! Most of the parts are 58 inches long. No other way but waste it. If I put them on 5x5 Baltic birch it fits better, but it won't fit in my van and it will cost a lot more.

Time to go pray that Kirsti Ally gets kicked of the dancing show.  :thumb:
Title: Re: DTQWT-12
Post by: stereofool on April 19, 2011, 06:45:57 PM
Baltic Birch would make a better cabinet...you know  :twisted:!

I can come over in my pick-up and we can make a plywood run.
Title: Re: DTQWT-12
Post by: richidoo on April 19, 2011, 09:39:33 PM
I'll check prices. One vendor says they sometimes stock it in 4x8. I can borrow a friends pickup like I did last time I bought some. I'm planning on double layering the sides anyway, so I think that with cheap ply will be better than one layer of BB.  Anything's better than MDF. Another idea is the greenglue sandwich of 3 or 4  1/4" layers - practice what I preach, damping quiets better than mass. Lots of work though. Thanks for offering Steve.
Title: Re: DTQWT-12
Post by: Carlman on April 20, 2011, 08:36:45 AM
Sounds very promising, and fun!  Enjoy! :)
Title: Re: DTQWT-12
Post by: Rob S. on April 20, 2011, 12:12:16 PM
All Right Rich,
         This will make a fun read over the next 29 days.  Looking forward to all the pictures.  :thumb:

Rob S.
Title: Re: DTQWT-12
Post by: rollo on April 21, 2011, 06:35:02 AM
 Hey Rich what about a 2" thick Spruce front and laminated Bamboo ply for the rest ? Check out The Mother of Tone Site. He likes Spruce. www.mother-of-tone.com


charles
Title: Re: DTQWT-12
Post by: richidoo on April 21, 2011, 07:29:32 AM
It will be 1.5" thick near the midrange driver with side wall bracing close by. That worked pretty good on the ELips even with much larger Mms and less well braced drivers than this box will have.

I tried pine with various Feastrex projects. Sounds good on some music, not on others, because resonance of spruce is nonlinear and too high frequency. It colors midrange too much. Some people like this and buy speakers like Musical Affairs or Ocellia which are built like a violin. They sound great on string quartets. Spruce's nonlinearity is perfect for a musical instrument where the artist wants a unique, personal sound, different from other violins. It is not suitable for a speaker that has to reproduce all other musical instruments because it resonates in a non linear way. IMO, fidelity is better than beauty in a speaker. I can add sweetening if necessary in a more controlled and linear way with tubes or magnetics, they are linear in audio band so there will be no nasty sounds at one freq. like a pine speaker does. And I won't find myself listening to only music that sounds good on those speakers. I want the next speakers to be good on any music.  Thanks rollo!
Title: Re: DTQWT-12
Post by: rollo on April 21, 2011, 08:16:50 AM
It will be 1.5" thick near the midrange driver with side wall bracing close by. That worked pretty good on the ELips even with much larger Mms and less well braced drivers than this box will have.

I tried pine with various Feastrex projects. Sounds good on some music, not on others, because resonance of spruce is nonlinear and too high frequency. It colors midrange too much. Some people like this and buy speakers like Musical Affairs or Ocellia which are built like a violin. They sound great on string quartets. Spruce's nonlinearity is perfect for a musical instrument where the artist wants a unique, personal sound, different from other violins. It is not suitable for a speaker that has to reproduce all other musical instruments because it resonates in a non linear way. IMO, fidelity is better than beauty in a speaker. I can add sweetening if necessary in a more controlled and linear way with tubes or magnetics, they are linear in audio band so there will be no nasty sounds at one freq. like a pine speaker does. And I won't find myself listening to only music that sounds good on those speakers. I want the next speakers to be good on any music.  Thanks rollo!


 No, thank you I learned something today.


charles
Title: Re: DTQWT-12
Post by: tmazz on April 21, 2011, 09:33:16 AM
This will make a fun read over the next 29 days. 


If e-lips was any indication this will be much more than a 29 day project!  8)

Which is not necessarily bad for us since I thought e-Lips was a great thread.  :thumb:
Title: Re: DTQWT-12
Post by: tmazz on April 21, 2011, 09:37:02 AM
It will be 1.5" thick near the midrange driver with side wall bracing close by. That worked pretty good on the ELips even with much larger Mms and less well braced drivers than this box will have.

I tried pine with various Feastrex projects. Sounds good on some music, not on others, because resonance of spruce is nonlinear and too high frequency. It colors midrange too much. Some people like this and buy speakers like Musical Affairs or Ocellia which are built like a violin. They sound great on string quartets. Spruce's nonlinearity is perfect for a musical instrument where the artist wants a unique, personal sound, different from other violins. It is not suitable for a speaker that has to reproduce all other musical instruments because it resonates in a non linear way. IMO, fidelity is better than beauty in a speaker. I can add sweetening if necessary in a more controlled and linear way with tubes or magnetics, they are linear in audio band so there will be no nasty sounds at one freq. like a pine speaker does. And I won't find myself listening to only music that sounds good on those speakers. I want the next speakers to be good on any music.  Thanks rollo!

Wow, I never realized that different woods had such a drastically different sonic signature. 

Although I don't know why the wood selected wouldn't alter the sound, everything else does.  :duh
Title: Re: DTQWT-12
Post by: richidoo on April 21, 2011, 10:09:55 AM
If e-lips was any indication this will be much more than a 29 day project!  8)

I hope not, this is just a big box.  :rofl:
Title: Re: DTQWT-12
Post by: richidoo on April 26, 2011, 07:24:42 PM
I bought the wood today. Home Depot has some really nice American made Appalachian hardwood plywood now, something new since last summer. Nice birch veneer with a good amount of grain, should look nice stained.
http://www.homedepot.com/hdus/en_US/DTCCOM/HomePage/Commerce/Building_Supplies/Lumber_Composites/Docs/HD_Core_Guide_9910.pdf

I spent some time laying out the cutting plan to make the pair of speakers fit onto 3 sheets with minimal waste. I was able to get all the grains to line up the way I wanted. One internal part will have a splice. Hope to start cutting tomorrow.

 
Title: Re: DTQWT-12
Post by: Carlman on April 29, 2011, 09:12:05 AM
This is the weekend for outdoor comfort.  It is about as nice as it can be out there right now.. Hope you get a lot done, Rich..
Title: Re: DTQWT-12
Post by: richidoo on April 29, 2011, 10:38:36 AM
Cut cut cut, almost all cut up now. I have three helpers home on vacation.

This weekend has 4 baseball games, 3 soccer games so it will be busy.
Title: Re: DTQWT-12
Post by: tmazz on April 29, 2011, 11:00:17 AM
This weekend has 4 baseball games, 3 soccer games so it will be busy.

Don't complain too much. Before you know it all you'll be getting out of them is "Hi Dad, can  have the car keys" and you'll be wishing there was a ball game you could take them to. I know I do. (At least number 2 son has gotten into vinyl and tubes, so we still have that to do together.  :D)
Title: Re: DTQWT-12
Post by: richidoo on April 29, 2011, 01:50:00 PM
No complaints here. Baseball is much more fun than speaker building. My middle son pitches his first game tonight. woohoo!

But I am glad to have gotten all the big boards cut down to rough sizes, and some final parts made.
Title: Re: DTQWT-12
Post by: rollo on April 30, 2011, 06:50:54 AM
No complaints here. Baseball is much more fun than speaker building. My middle son pitches his first game tonight. woohoo!

But I am glad to have gotten all the big boards cut down to rough sizes, and some final parts made.

  Nothing like it Rich. Coached Little Leauge for several years. The memories are priceless. Enjoy every moment. Hey tell your Son good luck today. The speakers can wait. Can you say no hitter?  :thumb:

charles
Title: Re: DTQWT-12
Post by: richidoo on April 30, 2011, 08:22:47 AM
Thanks Charlie! I love watching little league because every pitch has all the action of a entire major league game - IF you have a sense of humor.  :D  Henry did great for his first time, got 3 strikeouts in 2 innings.  :dj:

My oldest son has 2 games today, and two games tomorrow, at the field complex where the US Olympic baseball team practiced. All baseball all the time around here.
Title: Re: DTQWT-12
Post by: richidoo on May 20, 2011, 02:46:57 PM
I've been slackin off, but now all the parts are now cut to size and mitered, ready to glue. The homemade cross cut sled was a bit cloogey, but it worked OK.

The midrange/tweeter baffle is made of 18 x 1.5 pieces laminated together so that the plys are perpendicular to the vibration force, and those are made, ready for routing the driver holes.

I ordered a roll of rubber asphalt roofing membrane (http://www.gaf.com/Roofing/Commercial/Products/Modified-Bitumen-Roofing/Ruberoid-Modified-Bitumen-SBS-Membranes/Documents/Ruberoid__SBS_Heat-Weld_Smooth_-_Data_sheet-88-370-v1.pdf) as a damper to glue inside the plywood. It is extremely thick and heavy and will damp vibrations well. It is by far the cheapest damping material out there. But it has to get trucked in here from the distributor's warehouse in Charlotte, and I'm not sure how long that will take. Whenever the next inter-warehouse transfer occurs. I am not paying for the shipping, so I can't complain. It is 105 pounds per oversized roll, so shipping by means is not an option. I am tempted to proceed without it, but from past experience I know I will regret not damping the panels. Meantime I will route the driver holes.  Then I can do the crossovers until the damping arrives.

I read about asphalt (bitumen) pad as panel damper on the speaker designer's website, and could only find audiophile parts sources of it which were too expensive for the amount I need, and likely stink like petroleum. I looked at the damping sheets available for car audio, dynamat and such. All are too thin, too low mass and way too expensive. I went to HD and smelled the tar products they had there. The products made by GAF who makes my stuff did not smell, but the other brands did. So we'll see when it arrives.

The idea is to brace the panels so the minimum unbraced span is small. Then the minimum frequency is high, which is easily damped. The asphalt is huge internal friction and high mass, so it's a good damper.

Pictures coming.
Title: Re: DTQWT-12
Post by: richidoo on May 20, 2011, 03:47:00 PM
(http://www.audionervosa.com/MGalleryItem.php?id=786)

(http://www.audionervosa.com/MGalleryItem.php?id=787)

(http://www.audionervosa.com/MGalleryItem.php?id=788)

(http://www.audionervosa.com/MGalleryItem.php?id=785)
Title: Re: DTQWT-12
Post by: stereofool on May 20, 2011, 04:33:12 PM
Get going...boy  :twisted: :pop!!!
Title: Re: DTQWT-12
Post by: Tdangelo on May 20, 2011, 04:59:00 PM
Dang Rich, that's a lot of wood  :D
Title: Re: DTQWT-12
Post by: richidoo on May 20, 2011, 08:07:44 PM
Dang Rich, that's a lot of wood  :D
twss

Hey Tony! Actually, the pair takes 3 full sheets of 4x8 plywood, with very little waste. I have to be careful not make any mistakes or I will be heading back to depot. There are 4 pieces of the largest part (speaker sides) but only 2 showing. I cut those 1/8" proud on all sides, so I can use a flush trim router to get a perfect corner easily, that's the plan anyways, stay tuned..

The bass woofers are very lightweight. Lighter than the midrange drivers. When it arrived I picked up the shipping box up easy, worried that they didn't pack all 4 in there, but they did. The previous AE woofers were 24 pounds each, but these seem like 24 lbs for all four!
Title: Re: DTQWT-12
Post by: Bunky on May 20, 2011, 09:08:18 PM
Hey Rich,i think it is really neat that you can build your own loudspeakers.i make my living working with metal. i built a 12'x40' deck on the back of my little sisters colonial home but that is the only time that i have worked with wood and that is simple carpentry and does not require the precision that woodworking does. if i have more free time in the future building loudspeakers is something that i would like to try my hand at .
Title: Re: DTQWT-12
Post by: richidoo on May 21, 2011, 05:57:51 AM
William, I get a charge out of building with wood. Same feeling as working in the garden. It rejuvenates me. I'd actually like to learn how to weld so I can make speakers from metal!  :lol:
Title: Re: DTQWT-12
Post by: richidoo on May 26, 2011, 11:29:14 AM
Ruberoid damping material is in! I'll pick it up tomorrow and proceed with the build.
Title: Re: DTQWT-12
Post by: richidoo on June 03, 2011, 02:42:52 PM
(http://www.audionervosa.com/MGalleryItem.php?id=795)

I had a fun time outside today carving the front baffles. They are 1.5" thick 11.5 x 18.25" layered 3/4" plywood so the plys are parallel to the driver axes. The extra stiffness in that orientation will raise the baffles' resonance higher in frequency, which means less energy, which makes for easier bracing and damping.   But it's a lot of extra work.  I like the look of edge-on plywood lam although this is a little more wild look than baltic birch seen on Magico et al due to more blemishes on the inner plys. This front baffle center section will be surrounded by normal veneer above and below, with the edges of the side panels of the speakers showing on the front baffle top to bottom and blending in with this center panel in the middle.  It looks good in my mind so far...  :D

A picture of the front of the baffle on the left and rear of the baffle on the right. The midrange driver hole has a miter relief on the rear to allow easier breathing into the rear horn. The tweeter waveguide is installed and routed right though to allow some overlap of the drivers and reduce the distance between acoustic centers. The crossover is already designed so the driver geometry has to match the plan. I hate to cut these beautiful waveguides, but that's the design.

My jasper circle cutting jig has minimum 1/16" diameter increments. The wave guide hole was perfect fit, but the mid hole could have been a touch smaller. A CNC would be a nice tool to have... :)  But I love the woodworking.

The woofer holes  are larger than the rear baffle board width, so I must assemble the boxes before I cut those. So the next step, finally, is assembly! Then internal panel bracing, gluing the Ruberoid membrane, wood finishing, crossovers.
Rich
Title: Re: DTQWT-12
Post by: Face on June 03, 2011, 04:26:54 PM
Very cool! 
Title: Re: DTQWT-12
Post by: richidoo on June 16, 2011, 02:33:37 PM
Nice weather has allowed some quality saw time. Carcass of first speaker 2/3 done.  Pics:

(http://www.audionervosa.com/MGalleryItem.php?id=824)

(http://www.audionervosa.com/MGalleryItem.php?id=825)

(http://www.audionervosa.com/MGalleryItem.php?id=826)

(http://www.audionervosa.com/MGalleryItem.php?id=827)

(http://www.audionervosa.com/MGalleryItem.php?id=828)
Title: Re: DTQWT-12
Post by: stereofool on June 16, 2011, 02:47:07 PM
You weren't kidding about the size  :shock:!!! SO...size DOES matter  :rofl:.
Title: Re: DTQWT-12
Post by: richidoo on June 16, 2011, 02:48:46 PM
TWSS

Hey Steve! They are big. The pics don't look so big as they are. They will be 60" tall with the footer. 13" wide, 25" deep.

The rear (larger of the two) corner deflectors is too big, so it projects into the horn too far and would constrict the flow at the turn, so I have to chop it out and try again. It is glued in ready for nuke war so I am borrowing a sawsall from a friend tonight. Other than that it is going together pretty easily.

The front baffle upper and lower parts have a layer of MDF laminated to the front panel of ply. The center section of front baffle is 1.5" on edge ply lams.

If you look in the last pic you'll see lines drawn on the base panel for another internal panel for the front driver horn. I did not glue that in yet because I will need room to get the sawsall in there.

Title: Re: DTQWT-12
Post by: ebag4 on June 16, 2011, 04:41:32 PM
I'm really digging the front laminated baffle Rich, too cool! :thumb:

Best,
Ed
Title: Re: DTQWT-12
Post by: richidoo on June 16, 2011, 04:53:23 PM
Thanks Ed, I think it will look pretty cool when it's varnished. 

I'm still getting used to the size of this thing standing up in the living room.  :shock:  The designer said, "I'm sure only a few will apply for a total of 600 liters cabinets in their living room as these will require. The cabinet has grown to almost 152 cm height and 33 x 60 cm (WxD), so these are quite big speakers with brutto volumes of 297 litres."

Maybe I should paint them flat black and shine spot lights on them from above so they look like Space Odyssey obelisks.
Title: Re: DTQWT-12
Post by: rollo on June 17, 2011, 05:02:14 AM
  Looking good there. Dave Wilson should be afraid. :lol:


charles
Title: Re: DTQWT-12
Post by: richidoo on June 17, 2011, 05:18:11 AM
  Looking good there. Dave Wilson should be afraid. :lol:

 :rofl:
Thanks Charles
Title: Re: DTQWT-12
Post by: TomS on June 17, 2011, 05:36:17 AM
Those are looking very good Rich  :thumb:

As I look at those pictures, I'm just trying to imagine what evil would happen to me if I used those nice granite counters in my own kitchen for speaker assembly. Domestic harmony would be severely rattled or at the least I would be banned to the man cave for some suitably long term. You definitely rule, man!

Tom
Title: Re: DTQWT-12
Post by: djdube525 on June 17, 2011, 05:44:39 AM
I'm just trying to imagine what evil would happen to me if I used those nice granite counters in my own kitchen for speaker assembly. Domestic harmony would be severely rattled or at the least I would be banned to the man cave for some suitably long term. You definitely rule, man!

Same exact thought immediately popped in my mind.
Title: Re: DTQWT-12
Post by: richidoo on June 17, 2011, 06:12:28 AM
Haha! My wife is very tolerant of my errant ways, and I am very careful. The granite is flat and inside is cool, so it's hard to resist. She is an angel, and I am very lucky.
Title: Re: DTQWT-12
Post by: tmazz on June 17, 2011, 03:37:32 PM
I'm just trying to imagine what evil would happen to me if I used those nice granite counters in my own kitchen for speaker assembly. Domestic harmony would be severely rattled or at the least I would be banned to the man cave for some suitably long term. You definitely rule, man!

Same exact thought immediately popped in my mind.

+1
Title: Re: DTQWT-12
Post by: richidoo on June 17, 2011, 04:58:02 PM
The first speaker is built and ready for bracing and damping. Removing the wrong size corner deflector was very easy. Sawsall chop down the edges, then knock off the bottom joint, then my heat gun and putty knife removed the wood/glue residue, sand smooth and ready for the right size part, which was fitted to perfection this time, but with MDF since I have no spare ply. This plan fills three 4x8 sheets completely.

Note the hole in the front horn panel for clearance around the midrange magnet. It will be sealed with a piece of thin wood.

After treating the interior I'll glue on the other side (pretreated) and then flush route the edges around the sides. So the edge is still proud now. Fun day today!  Lots more to go.

I ordered more acousta-stuff today after I saw how big they really are! I had 1 pound bag because I was thinking I would build the smallest version of these. Then I decided to build the big daddy but I need a lot more stuffing for the closed tips of the horns (at bottom of speaker.)
 
(http://www.audionervosa.com/MGalleryItem.php?id=829)

(http://www.audionervosa.com/MGalleryItem.php?id=830)

(http://www.audionervosa.com/MGalleryItem.php?id=831)

(http://www.audionervosa.com/MGalleryItem.php?id=832)

(http://www.audionervosa.com/MGalleryItem.php?id=833)

(http://www.audionervosa.com/MGalleryItem.php?id=834)
Title: Re: DTQWT-12
Post by: Rob S. on June 19, 2011, 10:45:58 AM
Wow, looks great!

Rob S.
Title: Re: DTQWT-12
Post by: hometheaterdoc on June 19, 2011, 12:53:30 PM
I've got a garbage bag full of acousti stuff if you want it, rich...  one more thing taking up space in the garage......

they're looking good...  when do we get to listen again?
Title: Re: DTQWT-12
Post by: richidoo on June 19, 2011, 02:10:13 PM
Perfect timing Shane, thanks a million!

My kids' calendar is totally clear now for at least a month so hopefully I will be able to finish up all my audio projects this month. I'm on a roll now so things should come together fairly quickly. I'm really craving to have a meet and see everybody again. Probably towards end of July. I'll book it this week.
Title: Re: DTQWT-12
Post by: tmazz on June 19, 2011, 02:52:36 PM
......hopefully I will be able to finish up all my audio projects this month.

Rich, you have got to be kidding. If you are lucky you will get to finish up the projects you are currently working on by the end of the month. But as the Grand High Master of Nervosa I have no doubt that you will have your next three projects scetched out in your mind before the stain is dry on these speakers.  :rofl:  (Not that this is a bad thing, mind you, I wish I had 1/2 your energy. I get tired just reading about all that you do. :roll: )

You, my friend, will not be finished with all of your audio projects until the day they throw the dirt on you.... and loving every minute of it.  :thumb:
Title: Re: DTQWT-12
Post by: richidoo on June 19, 2011, 06:04:10 PM
You're right Tom, I meant the projects I already own but have been gathering dust since this time last year when I had my last big energy burst. Speakers, acoustic treatments and the new DAC.

But I do have a couple other ideas brewing... more vinyl antics, more acoustic treatments, Sol's IC headphone amp, Sonos linear power supply, FM tuner upgrades, on and on it goes. My previous hobby was RC sailplanes. I learned a valuable lesson from model airplanes over the years, that crashing is fun because you can build something new! The learning is always the funnest part for me.
Title: Re: DTQWT-12
Post by: mdconnelly on June 21, 2011, 04:57:45 AM
Looking great Rich!!   I cannot imagine how you'll finish them before the end of July but have no doubt you will!

Hey, avoid July 23rd weekend on the G2G - my daughter is getting married!  They wouldn't understand if I blew off her wedding for my audio buddies  :rofl:
Title: Re: DTQWT-12
Post by: tmazz on June 21, 2011, 05:07:17 AM
Looking great Rich!!   I cannot imagine how you'll finish them before the end of July but have no doubt you will!

Hey, avoid July 23rd weekend on the G2G - my daughter is getting married!  They wouldn't understand if I blew off her wedding for my audio buddies  :rofl:

You know our wives put up with a lot related to our audio madness, but I think that one just might be a just a bit over the line.  [-X
Title: Re: DTQWT-12
Post by: richidoo on June 21, 2011, 09:36:39 AM
Looking great Rich!!   I cannot imagine how you'll finish them before the end of July but have no doubt you will!

Hey, avoid July 23rd weekend on the G2G - my daughter is getting married!  They wouldn't understand if I blew off her wedding for my audio buddies  :rofl:

And we wouldn't understand if you blew us off just for the wedding! haha Congrats!!

I will avoid July 23 weekend. They better be finished by then! I originally said done by end of May. Then my energy pooped out and I lost a few weeks. I got the second one mostly glued up yesterday, it will finish today. It went a lot smoother than the first one. Then start the bracing. More pics when I do the bracing.
Title: Re: DTQWT-12
Post by: Bigfish8 on June 21, 2011, 06:26:06 PM
Rich:

I must admit to be totally overwhelmed by the size of your new babies.  I hope they exceed your expectations and just blow you away!

Ken
Title: Re: DTQWT-12
Post by: richidoo on June 22, 2011, 04:21:31 AM
Me too Ken! Thanks
Title: Re: DTQWT-12
Post by: richidoo on June 23, 2011, 11:11:49 AM
Both speaker boxes are built!

 :dj:

Now it's time for internal bracing. Bracing does not stop vibrations. All a brace can do is shorten an unsupported span. In doing so, the brace works like a finger on a guitar string. The string still vibrates, but at a higher frequency. The panel vibrating at higher frequency has much less energy than if it were vibrating at low frequency, so it is easier to damp. More on damping later. But for now I am trying to decide the geometry of the bracing.

The tri corners are the most rigid mechanical ground of the speaker, with side corners next best. I would like to refer the bracing to glued corners in some way to get extreme rigidity from the brace. The designer's plan calls for bracing which connects the center of one membrane to the center of the opposite panel. So in theory, both can vibrate together in sympathy, which they would do because they are made from same material and have the same span. Connecting the braces to the immovable corners will stop the membranes from moving.

The problem is that the bracing must be built into the speaker before the side panel is glued on. I am skinny, but not skinny enough to climb up inside the horn, so the bracing and damping has to be finished before the side lid can be glued on. The good part is that when a brace is viewed as a strut to raise freq then all considerations of strength and beefiness are out the window and only a small contact area and thin rod is necessary. Picture carbon suspension struts on a race car.

I think I will use 3/4" square rods cut from plywood, but the alternatives are wood dowel, or steel strapping. Steel would require bending a bead to stiffen it. Whatever material I use for strut I will dampen the strut vibes later.
Title: Re: DTQWT-12
Post by: Face on June 23, 2011, 07:43:22 PM
I intend on trying this stuff out for panel dampening on my next project.  http://www.gaf.com/Roofing/Residential/Products/Leak-Barriers/StormGuard-Leak-Barrier/StormGuard-Leak-Barrier.aspx
Title: Re: DTQWT-12
Post by: richidoo on June 24, 2011, 07:22:04 PM
That looks cool. Is it heavy?

I abandoned the elegant bracing approach. I am starting to get bored and need to see some serious progress. The bracing in the designer's plan is good enough. This way if it rings it will be his fault.  :rofl:   If I really love the speaker except for the noisy box I can build it again with quieter materials.

The braces are all cut and fitted to the approximate locations on the plan. There are no dimensions given so I had to scale them up from the plan. I need to install the damping material on the speaker walls and on the bracing before I glue in the braces.

The damping material is very heavy, a rubber and asphalt mixture with FG cloth interior. Bitumen is traditional roofing material made from asphalt, but it stinks. This has rubber mixed in with the tar which makes it more dense and stops the stink. Two layers of this on everything will knock down mid and higher frequency resonances. It is .1" thick. Did I say very heavy? The roll is 105 pounds! It has a heat sensitive adhesive on one side, but I will use some non stinky contact cement also. I am procrastinating because it is a new skill I've never done before. I'm sure the second speaker will come out better than the first...
Title: Re: DTQWT-12
Post by: Face on June 24, 2011, 07:30:05 PM
It has some mass to it, but it doesn't sound as dense as yours.  Do you have a link to what you just described?
Title: Re: DTQWT-12
Post by: richidoo on June 24, 2011, 08:07:52 PM
Here you go Face:
http://www.audionervosa.com/index.php?topic=3070.msg37684#msg37684

I got mine from Bradco Supply a subsidiary of ABC Supply. There are a lot of warehouses around the country. My local warehouse in Raleigh did not have it in stock, but they transferred a roll up from Charlotte warehouse for free.  Total was about $80. I learned about it from the speaker designer Troels Gravesen published an email from a guy who used it with good results.
http://www.troelsgravesen.dk/tips.htm   scroll down to "Mail from Michael."
Title: Re: DTQWT-12
Post by: richidoo on June 29, 2011, 07:11:14 AM
I have all the bitumen sheets cut to size and ready to  glue them in. The low odor contact cement does not work well at all. Apparently the sticky window in the drying time is very narrow, or is just sucks. Back to the store for the full odor good stuff.   Also discovered that the contact cement doesn't stick to the heat activated adhesive on the back of the bitumen. My heat gun was hot enough to melt the tar substrate but not hot enough to activate the heat glue layer.  :roll: It is just a thin layer of polyethylene-like plastic, so I'm not surprised glue won't stick to it, it is meant for torch heating and a huge roller.  Worst case I'll stick it on with 3M Super77 but I would prefer more control over where the glue goes because I still have wood parts to glue on and don't want to contaminate those spots.   

A little frustrating right now! But nothing we can't figure out. My son graduated from elementary school yesterday so he is home helping me out.
Title: Re: DTQWT-12
Post by: richidoo on June 29, 2011, 05:36:35 PM
Henry and I figured out a system to streamline the bitumen install, and it works good. I completed bitumen on the first speaker tonight. My fingers are covered with 77 glue, mixed with tar and garage floor soot, and it doesn't wash off. We had finger food for dinner tonight and my girl was grossed out when I licked the olive oil off my blackened fingers.  :rofl:

Super77 works good. Spray it on heavy and place it on the wood immediately. The carrier solvents will evaporate into the wood quickly to tack it on. Within 10 minutes it is permanent. Next time I buy the Rubberoid I will get it without the heat "glue" on the back. On some of the pieces the glue layer was loose from the tar and had to be peeled off before I could use 77.

The bitumen does help to take down the higher freqs of the wood resonance. Even on a knock test of a 12 x 12" MDF board the improvement was obvious. The lower freqs still remain though, which is why bracing is so important.

I installed all the braces into the cabinet after the bottom half of bitumen was installed.  Then I used a couple pieces of wood blocks to jig the braces to the center height. Then I did the bitumen on the top half.

Tomorrow I do the bitumen and braces on the other speaker, then felt and acoustistuff and I can close it up.

Pics coming.
Title: Re: DTQWT-12
Post by: richidoo on June 29, 2011, 07:38:30 PM
Some pics:

(http://www.audionervosa.com/MGalleryItem.php?id=842)
Braces, not glued, before damping, from bottom of speaker

(http://www.audionervosa.com/MGalleryItem.php?id=838)
Braces, from top

(http://www.audionervosa.com/MGalleryItem.php?id=836)
GAF Ruberoid rubber modified bitumen roofing membrane. See previous post for product details. Get the plain unglued version for hot tar application. not the heat and stick version.

(http://www.audionervosa.com/MGalleryItem.php?id=844)
10 x 1 meter x 0.1" thick, cut in half, flattening in the sun. Like my roses?   :rofl:

(http://www.audionervosa.com/MGalleryItem.php?id=840)
Damping bitumen installed. What a bitch of a job. But it works!

(http://www.audionervosa.com/MGalleryItem.php?id=845)
Detail of damping and braces, rear bass horn, looking from top. The bass drivers are separated by the narrow brace closest. No damping is needed near the woofers due to their frames' rigidity.

(http://www.audionervosa.com/MGalleryItem.php?id=843)
Braces are damped both sides. Bottom of front horn is not damped, due to no room to install it, and front baffle is already two layers of dissimilar wood, ply and MDF, laminated together with glue.

(http://www.audionervosa.com/MGalleryItem.php?id=841)
Brace and damping detail, looking from top.

(http://www.audionervosa.com/MGalleryItem.php?id=837)
This is the side (aka lid) with the damping. The internal baffle edges and braces will glue to the undamped strips and holes.  And yes, it fits! After a bit of trimming. On the second speaker I was able to mark the location of internal baffles on the lid better than the first speaker, so the damping of the second lid will be easier, because the lines are accurate.
Title: Re: DTQWT-12
Post by: djdube525 on June 30, 2011, 02:32:22 AM
I see you got booted out of the kitchen once you started working with the GAF Ruberoid material.  :rofl:

I'm amazed at how quick the progress is coming along. Looking really good!

Dave
Title: Re: DTQWT-12
Post by: richidoo on June 30, 2011, 07:01:57 AM
Thanks Dave!

I moved outside mostly because of the fumes of the glue, but you're right the raw material is clean but the installation process is dirty. I'll be using the same glue again for the felt, then I'll start the wood finishing which will also require ventilation. But I'll be back inside asap!
Title: Re: DTQWT-12
Post by: rollo on June 30, 2011, 08:58:37 AM
Richidoo looking good there. Does the Bitumem have an odor ?



charles
Title: Re: DTQWT-12
Post by: richidoo on June 30, 2011, 09:19:53 AM
Yes, but it is very slight. I must hold it up to my nose to smell anything, and even then it is slight. It is a cross of petroleum and rubber. Old school "bitumen" was canvas dipped in asphalt. This is FG cloth with a layers of rubberized tar on each side. The rubber seems to lock in the odor of the tar. A couple weeks ago before I ordered it I visited Home Depot to smell the roofing products.  :shock:   The other brands had a very strong asphalt odor, but all the GAF products with rubberized asphalt had hardly any smell.

After I cut the bitumen pieces to size, I kept them inside for a couple days, warehoused in the dining room, of course. Nobody smelled anything. I have a bionic sense of smell, and I couldn't smell it at all. So it should be OK. I was worried about it until I smelled the GAF products at home depot. Then I ordered it with small chance of stinking. Lucked out.

I think I would use GAF Ruberoid SBS Dual Smooth next time, without the heat weld film, which just peels off and prevents good adhesion to the speaker, but it is not quite as heavy. Good adhesion is more important for vibration treatment.  This stuff will work good inside component metal cases, as layers inside TT plinths, etc.

http://www.gaf.com/Roofing/Commercial/Products/Modified-Bitumen-Roofing/Ruberoid-Modified-Bitumen-SBS-Membranes/Ruberoid-SBS-Dual-Smooth.aspx
Title: Re: DTQWT-12
Post by: Face on July 01, 2011, 08:57:19 AM
I left a roll of Storm Guard in my car few a few hours on a sunny day, big mistake.  The car stunk for a whole day, and the roll itself had a strong odor for a few days.  I couldn't walk by it without making a disgusted face.   :rofl:
Title: Re: DTQWT-12
Post by: djdube525 on July 01, 2011, 09:04:22 AM
AHAHAHAHAHA...

Rich... I just noticed the caption under your Avatar - "Like a G-6"...

I never have paid attention to the lyrics in that song... except for that phrase. I was wondering why someone would write a song about a Pontiac.  :duh   :rofl:
Title: Re: DTQWT-12
Post by: richidoo on July 01, 2011, 10:07:10 AM
I left a roll of Storm Guard in my car few a few hours on a sunny day, big mistake.  The car stunk for a whole day, and the roll itself had a strong odor for a few days.  I couldn't walk by it without making a disgusted face.   :rofl:

That's funny Face!  A bottle of girl's hair conditioner leaked in my car back in college. Talk about stink! I don't know why I was with a girl that deliberately tried to smell like that. Oh, yeah, now I remember.  :roll:

Pontiac G6   :lol:   "Like a G6" (http://www.youtube.com/watch?v=GvgJEznqtms) by Far East Movement. One of my favorite songs of all time!!  :thumb:
Title: Re: DTQWT-12
Post by: richidoo on July 01, 2011, 10:15:37 AM
All the bitumen damping is installed. My knees are black and my back is killing me.

I also cut out all the felt pieces that will be glued inside for acoustic damping. I am using this felt
http://www.rugpadcorner.com/superior-felt-jute-rug-pads.aspx
It is thick, dense and luxurious, it would even make a nice carpet pad! This will be all glued in by today.

I picked up a bunch of Acoustistuff from Shane last night, thank you sir!  That will go in the closed ends of each horn for damping of the higher frequency peaks generated in the horn. Theoretically we only want the lowest resonance generated in the horn, but the upper harmonics also escape. Acoustic damping helps reduce the upper harmonics which would interfere with the midrange driver's contribution. That's one of the tradeoffs of horns / TL.

(http://www.troelsgravesen.dk/JA8008_DTQWT_cabs_files/DTQWT_cab_draw_damping.gif)
Green is the felt, yellow is the acoustistuff.  This pic is the smaller DTWT, not the  DTQWT-12.

Rich
Title: Re: DTQWT-12
Post by: richidoo on July 02, 2011, 08:35:21 PM
All bracing, damping and felt is installed. Interior wire holes and exterior binding post holes are drilled.

(http://www.audionervosa.com/MGalleryItem.php?id=849)
Felt at top of speaker

(http://www.audionervosa.com/MGalleryItem.php?id=852)
Rear horn with felt

(http://www.audionervosa.com/MGalleryItem.php?id=847)
Closeup bitumen and felt layers

(http://www.audionervosa.com/MGalleryItem.php?id=846)
Lid ready to glue to speaker

(http://www.audionervosa.com/MGalleryItem.php?id=848)
Midrange hole

(http://www.audionervosa.com/MGalleryItem.php?id=850)
Gluing cross braces with 90 degree angles and weights

(http://www.audionervosa.com/MGalleryItem.php?id=851)
Weights on shelfs. The cross braces were aligned with a T-bar perpendicular to the bottom. They lined up perfectly to the lid.


Next up:
Build the crossovers and install them with wiring and binding posts, but no drivers
Stuff the horns with acoustistuff
Glue on the lids
Trim the lid edges flush to the box with router and flush trim bit
Route the woofer holes (carefully!)
Sand, stain and varnish with General Finishes products.
Install drivers
Tip a cold one while the tubes warm up...  :thumb:

It is nice to be able to see the light at the end of the tunnel.... or is that a train?
Title: Re: DTQWT-12
Post by: ebag4 on July 02, 2011, 08:51:01 PM
Looking good Rich  :thumb:!  Even though it is a speaker with large panels it appears you are doing everything possible to keep the cabinets from resonating, well done.   I am curious why you haven't already routed the woofer holes, was there a specific reason that made it best to wait?

Best,
Ed
Title: Re: DTQWT-12
Post by: richidoo on July 02, 2011, 09:37:18 PM
Hi Ed,
The woofer's OD is 12.5", and the through hole is 11-1/2". The rear panel width is only 11-5/8". The mounting flange recess will cut into the side panels' edge. To flush mount the drivers I need to cut the mounting flange recess before I cut the through hole in order to use the same centering pin location so the recess and through hole are concentric. Recess must be cut before through hole, so the sides must be glued on before cutting the recess. A little trickier but no biggie.
Rich
Title: Re: DTQWT-12
Post by: djdube525 on July 03, 2011, 05:06:28 AM
And doing all of this in 95-100 degree heat... Now that's dedication! Hopefully, you're tipping up a cold one after each of these steps.

Thanks for the explanation about the woofer holes... I was wondering the same thing.
Title: Re: DTQWT-12
Post by: Carlman on July 03, 2011, 01:59:10 PM
Wow, that is impressive craftsmanship.  You have some great skills, Rich.  That design sure does have all the components of what I would think sounds good... I'm really looking forward to hearing them sing.  
-C
Title: Re: DTQWT-12
Post by: richidoo on July 03, 2011, 07:04:28 PM
Carl, Thanks for the compliment. My skills are improving with each project. I hope they sound good too.  I don't see how they cannot sound "good," considering the design and parts quality, and the rep of the designer Troels Gravesen. He is very well respected among DIY speaker builders. The smaller version of this, called DTQWT (twin 10" woofers) has been built a few dozen times and everybody seems to really love them. Mine are the same drivers and crossovers as DTQWT but with  larger interior horns for the bigger (12") woofers. Here's hoping!! They are still boxy plywood speakers so I don't think the cabinet will be as quiet as a 4" thick MDF hifi speaker, but I do hope they will sing and make good music. I hope they will be able to play big so i can enjoy symphonies again. The one other guy that I know of who has built these big ones says that symphonies are awesome with his mastersound 50W parallel 845 SETs.   If the cabs are too noisy I can add more meat to the outside. The interior reflections are the only other cause for concern from my experiences with previous horn speakers, but the felt should take most of that down.
Title: Re: DTQWT-12
Post by: Face on July 03, 2011, 07:18:12 PM
Nice work so far!

Using a Jasper jig for the driver cutouts? 
Title: Re: DTQWT-12
Post by: ebag4 on July 04, 2011, 09:11:18 AM
Hi Ed,
The woofer's OD is 12.5", and the through hole is 11-1/2". The rear panel width is only 11-5/8". The mounting flange recess will cut into the side panels' edge. To flush mount the drivers I need to cut the mounting flange recess before I cut the through hole in order to use the same centering pin location so the recess and through hole are concentric. Recess must be cut before through hole, so the sides must be glued on before cutting the recess. A little trickier but no biggie.
Rich
Thanks Rich, that is quite obvious now that you have explained it  :duh.  Looking great, can't wait to read your impressions.

Best,
Ed
Title: Re: DTQWT-12
Post by: richidoo on July 04, 2011, 10:03:07 AM
Face, I use the small Jasper 400 jig for the tweeter hole, and an older model medium sized Jasper for the mid and woofer holes, with a carbide 1/4 porter cable bit. I see that the new mid size Jasper (bottom pic) goes down to 2.25" diameter. Mine doesn't go that small so I have to use the small round jig for small circles.

(http://ecx.images-amazon.com/images/I/51GYK2H8WCL.jpg)
Small

(http://ecx.images-amazon.com/images/I/51XP4STEX3L.jpg)
Big
Title: Re: DTQWT-12
Post by: richidoo on July 04, 2011, 10:43:08 AM
Eminence woofer holes are 12 - 7/16" for flange, and 11" for the through hole.
Title: Re: DTQWT-12
Post by: Bunky on July 04, 2011, 01:18:51 PM
My god Rich how many manhours do you have in these beauties  :shock: your work looks very professional  :thumb:
Title: Re: DTQWT-12
Post by: richidoo on July 04, 2011, 01:53:24 PM
Thanks Bunky! Just don't look too close ;)

I do have quite a few hours in them, haven't been counting - but they are the most involved speakers I have built yet so I expected they would require good effort. I like the work, especially the woodworking. I don't look forward to steps that I have never done before, but after I learn how then it is fun. Some of the steps are fun than others, but I just keep murmuring  "one step at a time" under my breath to get through it. Today making 12 wire lengths for the hookups was pretty tedious, but gotta be done. Now I'm building the crossovers, that should be kinda fun, the parts are so pretty and I know they are awesome quality audio parts so it is exciting to bring them to life. I want to install the crossovers before gluing on the lid.

I look at it like Dr. Frankenstein, making a machine that will come to life, but I am slightly less passionate than him, fortunately.
Title: Re: DTQWT-12
Post by: mgalusha on July 04, 2011, 07:08:57 PM
Very cool indeed Rich, can't wait to hear your description of the results.

Not that you need one since you have a Jasper Jig but there is a widget called the Router Buddy (http://practical-technologies.com/) that will cut circles from 2" to 18" with no steps, so you can get any size desired. It does require measuring during setup but that is a simple matter with something like a dial or digital caliper. I found out the hard way that cutouts can be so precise that the drivers are a press fit. I forgot to allow for any clearance, cut the holes exactly the same size as the driver and they were hard to get in and worse to get out. Lesson learned. ;)

Title: Re: DTQWT-12
Post by: richidoo on July 04, 2011, 08:44:09 PM
Yup, I hate when that happens, hole cut too small and the centering pin is gone... especially in baltic birch which is hard to sand the hole bigger... Thanks for tip Mike. It looks like a nice tool, does just about everything too. I have often wished for finer resolution than Jasper's 1/16" min diameter. It won't be long before my router with small jasper rolls off the table saw (again.)

I was starting to get used to my midfi Infinitys, thinking they weren't too bad. Then I got to hear RichardS's new speakers this past Saturday. Peak Consult Zoltan, with full Tact electronics and 4 driver stereo subs. They sound even better than they look and they look like something out of the Bentley factory. Total refinement at any volume, and they are not even dialed in yet! Now I am much more motivated to finish my speakers asap. My goal is to hear them (in stereo) before I leave for Capital Audio Fest on Sat morning.
Title: Re: DTQWT-12
Post by: Face on July 05, 2011, 05:52:34 AM
I have both Jasper Jigs and the router buddy, I believe I used the router buddy once as it takes much longer to set up in comparison to either JJ. 
Title: Re: DTQWT-12
Post by: richidoo on July 06, 2011, 09:45:42 AM
A wicked lightning storm last night took out my internet so I was deprived of AudioNervosa and was "forced" to work on my speakers until midnight. My goal was to finish the crossovers yesterday, but there were a few things left to finish this morning. Behold, the brains:

(http://www.audionervosa.com/MGalleryItem.php?id=884)
2nd order midrange and tweeter filters together on the left, 1st order bass filter on the right.

(http://www.audionervosa.com/MGalleryItem.php?id=883)
With 12" woofer for scale.

The Jantzen electronic parts are extremely high quality. The mid and tweeter coils are copper foil dipped in hot wax to prevent mechanical motion between coils, which makes FM distortion. The bass coil is a huge toroidal core wrapped in thick copper windings. DCR is only  .17 ohms.  Silver Z caps to the tweeters, Superior Z caps to the mids, and non-inductive metal oxide film resistors.

It is looking cloudy so it may rain again today, which would prevent using the router outside to cut the woofer holes. But if it stays dry I'll make a mad dash to the finish today.
Title: Re: DTQWT-12
Post by: Carlman on July 06, 2011, 10:16:11 AM
Sweet!  Home stretch! :) :) :)
Title: Re: DTQWT-12
Post by: richidoo on July 06, 2011, 11:26:37 AM
One cool thing about this crossover is the ability to adjust the tweeter level. Three different resistors are provide, you can choose which one you want. You can see them all together at the top right. I have the largest value connected now, which is the preference of the designer, but I can increase the tweeter level (twice) if necessary. Just unsolder one resistor from the silver cap and solder on a different cap.

2 hours at the pool with the kids and now it is lightning storm again.  :roll:    Now you guys can see why I like battery powered audio system, or a Pure Power or Brick Wall protection.   Maybe with these speakers I can try battery amp again. Sol designed a 50W battery amp with bipolar battery supply (two batteries) but we never built it.
Title: Re: DTQWT-12
Post by: tmazz on July 06, 2011, 08:39:27 PM
2 hours at the pool with the kids and now it is lightning storm again.  :roll:   

Don't mess with lightning..... it fights back.  (http://i21.photobucket.com/albums/b297/GHGecko/ANI_GIFs/TINYs/Smiley_Tiny_Lightning_Strike.gif)
Title: Re: DTQWT-12
Post by: richidoo on July 07, 2011, 11:03:09 AM
Good weather and self occupied children are allowing progress today. One speaker is glued shut. Both should be ready for routing today. It is supposed to rain later, so routing the woofer holes may have to wait until tomorrow.
Title: Re: DTQWT-12
Post by: BobM on July 07, 2011, 11:43:42 AM
WAIT !!!!!

Didn't you forget to put the < insert part name here > into the cabinet before you glued it shut?  8-[ ](*,)

Measure twice, cut once, double check everything and I am guaranteed to still forget something until it is too late to do it easily.

Title: Re: DTQWT-12
Post by: richidoo on July 07, 2011, 01:06:07 PM
I was a little worried about that, so took a 1/2 hour break for lunch before I squirted the glue just to make sure my head was straight. I double checked the crossover circuits, hookup wire polarities, stuffing, whatever else I could think of. No doubt there will be something but per Murphy's Law I can't know what I forgot until it's all buttoned up!

Almost ready to close up the second one, but the weather will nix the routing for today. I'll be ready to do it tomorrow morning when it is calm.
Title: Re: DTQWT-12
Post by: richidoo on July 07, 2011, 03:32:54 PM
Some pics:

(http://www.audionervosa.com/MGalleryItem.php?id=892)


(http://www.audionervosa.com/MGalleryItem.php?id=894)


(http://www.audionervosa.com/MGalleryItem.php?id=890)


(http://www.audionervosa.com/MGalleryItem.php?id=891)


(http://www.audionervosa.com/MGalleryItem.php?id=885)


(http://www.audionervosa.com/MGalleryItem.php?id=886)


(http://www.audionervosa.com/MGalleryItem.php?id=887)


(http://www.audionervosa.com/MGalleryItem.php?id=893)


(http://www.audionervosa.com/MGalleryItem.php?id=889)


(http://www.audionervosa.com/MGalleryItem.php?id=888)

Title: Re: DTQWT-12
Post by: djdube525 on July 08, 2011, 01:51:12 AM
Ohhh... the lid is on... testing this weekend?
Title: Re: DTQWT-12
Post by: richidoo on July 08, 2011, 04:10:54 AM
Hopefully today!  Just have to do the routing this morning, mount the tweeter to the waveguide, then install the drivers. 3 hours tops.

Busy day - My son is playing in a championship tennis match at school at 7:30 this morning, then meet the teacher for 2 middle schoolers, then get the tires balanced, then sleepovers. If I can fit the routing in this morning after tennis then I should make it.
Title: Re: DTQWT-12
Post by: mdconnelly on July 08, 2011, 04:42:59 AM
Rich, it's just exhausting reading about all you're doing... :rofl:

Can't wait to see (and hear!) those speakers!
Title: Re: DTQWT-12
Post by: Carlman on July 08, 2011, 08:00:12 AM
I know Mike is kidding... but I really feel energized!  It's like watching a TV show where they cut out all the boring stuff and just show you progress points.  Thanks for sharing your enthusiasm during this project.  I'm encouraged to get my butt in gear and do stuff... Speaking of... better get to the garage myself... It's not going to clean itself! 8)

-C
Title: Re: DTQWT-12
Post by: rollo on July 08, 2011, 08:51:50 AM
   I hear NASA visited you to clone it. All the hard work will pay off.  :thumb:



charles
Title: Re: DTQWT-12
Post by: hometheaterdoc on July 08, 2011, 10:14:44 AM
whats with all the rigid fiberglass in the background, Rich??  Have you not finished all the acoustic panels YET? ;)

Title: Re: DTQWT-12
Post by: richidoo on July 08, 2011, 11:50:45 AM
Thanks guys!  Vitamins and LOVE... NASA can't clone that

FG is still piled up. I haven't touched that since last summer. But I intend to do more panels for the meet. I also have another 12 panels hidden away, reserved for a special project.   8)

I got both speakers' edges trimmed, and one speaker has the woofer holes cut.  Weather is unbelievable. I have to wipe myself off with a towel after every cut. Two more woofer holes and it's downhill.  I think I will make it before the rain.

I read the deHavilland website last night to get psyched up, so I am ready for tubes and tunes.

I was hopeful that this all American hardwood ply would be excellent, but there are some issues. In the future I will use only Baltic Birch for speaker projects.

OK enough procrastinating, back at it....
Title: Re: DTQWT-12
Post by: richidoo on July 08, 2011, 01:54:14 PM
All the holes are routed. Only minor steps left. Lift-off tonight, I hope.
Title: Re: DTQWT-12
Post by: lonewolfny42 on July 08, 2011, 04:17:48 PM
WOW....THAT'S AMAZING !!!!!


You don't always see that...... :duh


A two car garage that's clean and neat....nice work Rich !!! :thumb:




And.....the speakers look pretty good as well....

Good luck ...... :beer:






Title: Re: DTQWT-12
Post by: hometheaterdoc on July 08, 2011, 04:33:21 PM
It's actually a 3 car garage.... I have garage envy of him.... if I actually had a three car, I might be a bit more organized.... yeah... keep telling myself that....  :)

Title: Re: DTQWT-12
Post by: richidoo on July 08, 2011, 05:14:28 PM
Thanks LW. Julie parks inside, and I like to park inside too, so that only leave one for the junk. I was careful to avoid taking any pictures of that side. haha 

I brought the speakers inside, and started mounting the drivers, but there's too much left to do to finish them tonight. I'm pooped! Still have to pack and go to bed for the drive to CAF tomorrow.   They look even bigger inside.  :shock:
Title: Re: DTQWT-12
Post by: Face on July 08, 2011, 05:24:18 PM
I hate all the small details at the end too.

Looking forward to your impressions tomorrow.
Title: Re: DTQWT-12
Post by: tmazz on July 08, 2011, 08:10:40 PM
It's actually a 3 car garage.... I have garage envy of him.... if I actually had a three car, I might be a bit more organized.... yeah... keep telling myself that....  :)


Shane don't kid yourself, if you had more room you would just end up collecting more cr@p.  :rofl:

(Just like the rest of us.  :roll: )
Title: Re: DTQWT-12
Post by: richidoo on July 10, 2011, 08:06:19 PM
Back to work on the speakers tonight. I got the tweeters mounted to the waveguides, and I got a tweeter and midrange mounted into one speaker. Started the woofers and saw that the lid (side) had not bonded well to the rear baffle near the woofers so I had to reglue it. I need more clamps! Should be playing music tomorrow. All the talk of horns and SETs at the show really got my juices flowing to hear my new speakers.
Title: Re: DTQWT-12
Post by: richidoo on July 11, 2011, 10:44:11 AM
DTQWT-12s are alive!   :yay2:

They need varnish, break in, stuffing tweaking, more room acoustic treatments, but they are making noise now, a significant milestone.

They do sound huge, the bass is very powerful, detailed and errr.  Lower mid is a bit stuffy I'm hoping that will go away with break in, the woofers are very tight doped cloth suspension and low Q so break-in will change them alot. If it doesn't go away then more panel bracing is required.

After hearing the total metamorphosis of the Polk 705 speakers in their first 20 hours at the CAF I can imagine anything can happen during speaker break in. It is the same feeling I'm getting from these that I felt with them.

Right off the bat, the midrange / tweeter drivers and their crossover design sounds excellent. Open and alive, musically communicative. My head is bobbing already.
Title: Re: DTQWT-12
Post by: Bigfish8 on July 11, 2011, 10:45:00 AM
Back to work on the speakers tonight. I got the tweeters mounted to the waveguides, and I got a tweeter and midrange mounted into one speaker. Started the woofers and saw that the lid (side) had not bonded well to the rear baffle near the woofers so I had to reglue it. I need more clamps! Should be playing music tomorrow. All the talk of horns and SETs at the show really got my juices flowing to hear my new speakers.

I will be very interested to read your comments about the sound!  I hope they will be great!

Ken
Title: Re: DTQWT-12
Post by: richidoo on July 11, 2011, 10:46:40 AM
Thanks Ken! I hope they will be great too. In a week we'll know...

Pics:

(http://www.audionervosa.com/MGalleryItem.php?id=897)

(http://www.audionervosa.com/MGalleryItem.php?id=898)

(http://www.audionervosa.com/MGalleryItem.php?id=896)

(http://www.audionervosa.com/MGalleryItem.php?id=895)
Title: Re: DTQWT-12
Post by: bpape on July 11, 2011, 11:25:04 AM
 It's alive! :twisted:
Title: Re: DTQWT-12
Post by: Face on July 11, 2011, 03:35:16 PM
(http://img15.imageshack.us/img15/613/hannibaliloveitwhenapla.gif) (http://img15.imageshack.us/i/hannibaliloveitwhenapla.gif/)
Title: Re: DTQWT-12
Post by: richidoo on July 11, 2011, 04:21:20 PM
Sounding better and better! Upper bass is not damped enough, it will need more stuffing in the bass horn. I stuffed it lightly because I don't want to lose the life, but it needs more, the horn is ringing too much. Thanks to Shane I have plenty on hand.  :thumb: Bass is a little too loud for my taste also, so more stuffing will help both ways. I'll put it in through the woofer holes.

I tried to post a few hours ago, to tell Bryan that he inspired this speaker when he said horn loaded bass sounds awesome. I was searching for his post from 2 years ago and I changed the search words before the first search returned, and it crashed the server. Sorry guys! Carl was kind enough to call host from the beach to fix it. Moral: Be gentle on the AN search engine!

Anyway, thanks Bryan, for recommending horn loaded bass, ala Voight pipe... sorry I don't have the link..
Title: Re: DTQWT-12
Post by: richidoo on July 11, 2011, 04:37:39 PM
Impedance and Phase of DTQWT-12

(http://www.audionervosa.com/MGalleryItem.php?id=899)
Title: Re: DTQWT-12
Post by: hometheaterdoc on July 11, 2011, 05:01:33 PM
looking good, Rich... can't wait to hear them!!!
Title: Re: DTQWT-12
Post by: rollo on July 12, 2011, 06:44:40 AM
    Well done sir. Dem der woofers gonna need some time to loosen up. Time is on your side. Enjoy the fruits of labor there Rich.
    DIY is the real hobby.  :mrgreen: Now the art of fine tuning is upon you. enjoy every minute.


charles
Title: Re: DTQWT-12
Post by: Face on July 12, 2011, 01:11:17 PM
Some LF test tones will break those woofers in much quicker. 
Title: Re: DTQWT-12
Post by: bpape on July 12, 2011, 01:24:32 PM
Just put on Bela Fleck - Flight of the Cosmic Hippo on repeat. That'll break them in.

Bryan
Title: Re: DTQWT-12
Post by: richidoo on July 12, 2011, 01:42:19 PM
Thanks Charles!

The drivers / crossovers are opening up nicely. But the excessive warmth is still there. It's either panel resonance or interior echos. The main horn chamber is huge, with no absorption at all.

I played just the MT drivers without the woofers. There is excessive midrange warmth.
But actually the lowest frequencies don't have that much distortion. ~800Hz and up is clean. 100-800 rings but mostly 100-400.

The upper midrange and treble tone is absolutely gorgeous. Violins are perfect, clear, dense and sharp, but no hard drivers so it doesn't cut. Plenty of treble for real music, but not quite enough for audiophile recordings. I will try the next smaller tweeter resistor sometime.
Title: Re: DTQWT-12
Post by: richidoo on July 12, 2011, 05:00:24 PM
I don't have the cosmic hippo, but I do have a test track I made for breaking in Carl's TC sub. It is two bass notes played at the same time. I call it sub torture. It sounds like a Huey hovering over the house

Do you guys think some of the mid warmth could be from driver stiffness?
Title: Re: DTQWT-12
Post by: Face on July 13, 2011, 04:33:38 PM
Have you measured their in room and near-field response? 
Title: Re: DTQWT-12
Post by: richidoo on July 13, 2011, 06:50:11 PM
I have not yet. I know I want to tune them better anyway. But I guess running a baseline would be valuable. Thanks for the idea. I already have one opened up for stuffing so I'll do it after the first tweak.

I'm adding about 1.25 pounds of acoustistuff to each speaker, that's about double what's in there now. I like to overdo things and back off. I think it is more efficient than creeping up on a target a mile away. I have been reading a lot about TQWT designs today, and it is most likely that the internal acoustic resonances are the issue, not panel resonance, although there is some of that too, of course. I have some ideas to try to reduce the echos in the horn.
Title: Re: DTQWT-12
Post by: richidoo on July 14, 2011, 09:36:32 AM
Happily, adding stuffing cured the horn ringing, but I used too much by filling the whole rear horn. It is too soft and muffled, need to fine tune it.
Title: Re: DTQWT-12
Post by: richidoo on July 14, 2011, 10:45:29 AM
The lowest tweeter setting (biggest resistor) is more than enough, I discovered that I had Sonos treble attenuated for my Infinity speakers.

I think the bass horn damping is about right now. Lowest notes are not as loud as before but still deep. It will take several tries to figure out the best way. The midrange horn needs more damping too.
Title: Re: DTQWT-12
Post by: richidoo on July 14, 2011, 01:49:06 PM
Got the 300Bs playing now. Nice! Presence is up, and liquidity. It's still a bit too round and warm for my taste, but does sound lovely. There's more tweaking to do on the speakers yet, I want to try some absorption inside the main center horn, as I can hear midrange echoing in there. The roundness may also be coming from the rear speakers since they are only 1st order low pass filter and will naturally lose resolution as frequency rises. The designer invented a acoustic trap to catch the upper frequencies, so I'll give that idea a try too. Basically suspend some absorption in front of the woofers to catch the midband.

I played some symphony stuff, sounds pretty good! Organ music is awesome. I pulled some stuffing out of the bottom of the rear horn, leaving a tunnel down the middle with stuffing on the side walls, that restored the deep bass without the ringing. Basically the bass horn treatment is thick pads of stuff running up the side walls, nothing in the middle of the pipe, so the length is not affected at all.

I have a pass DIY B1 preamp on hand for volume control to allow playing vinyl, but it'll need its long procrastinated surgery for new caps before it plays. A little birdie told me that there is a nice tube preamp coming to visit with me very soon!  :thumb:
Title: Re: DTQWT-12
Post by: rollo on July 15, 2011, 12:18:21 PM
   Would Black Hole Pad be any help ? BTW the woofers really need to loosen up before you can make any real judgements.
   Give them some time there El Nervosian.  :rofl:


charles
SWA
Title: Re: DTQWT-12
Post by: richidoo on July 15, 2011, 01:59:06 PM
Thanks Charles. Black Hole is a good all around combination box treatment. It does some mechanical damping and some acoustic damping, but does neither as well as can be done with separate materials optimized for their job.  I'd need a couple yards ($) of it to do these, and it is too thick to fit in some of the places. I did the bitumen membrane for the mechanical damping, just like the dense layer in Black Hole that sticks to the wood except denser and thicker. Then the acoustistuff and FG panel that I am using is like the BH foam layer which converts air velocity (pressure changes) to heat for acoustic damping.

You are right about the break in. They have about 20 hours so far. I think all the drivers are changing some. The woofers opened up pretty fast and sound good now, but the mid has entered a sharp phase, or needs more damping. Weekend is here so I'll just let it play while I do other things.
Title: Re: DTQWT-12
Post by: richidoo on July 15, 2011, 02:02:07 PM
One nice thing is that my 24W push pull 300Bs can run with no feedback at all without any sign of stress of distortion. I needed at least 5dB for normal music when playing with Usher Be20, and max 10dB when I wanted max power from them, but of course it sucked the life out the music. Now I can play big music with 0-2dB feedback.
Title: Re: DTQWT-12
Post by: richidoo on July 19, 2011, 02:42:16 PM
OK, I think the speakers are basically finished. I finished the stuffing today. There is a lot more stuffing now, which cured the internal ringing from mids down through bass. It is slightly stuffier, but the annoying ringing is gone, clarity and control is excellent top to bottom and the efficiency is still excellent.

I also discovered some loose screws between tweeter and waveguide which allowed them to clang together, which could be responsible for the edgy treble I heard before. It is gone now, but could have just needed break in.  Overall, the speakers sound awesome, much, much more than I expected when I started. They play huge, with great mid tone, and tuneful, punchy bass  all the way down. No reflex smear here.

They can play very loud for hard rock, organs and symphonies, and they still sound great at medium levels for compressed music. Bass is very physical. I would estimate it plays solid down to 35Hz, with lowest organ fundamentals easy to hear but not as strong as my old Legacy Focus 2020s. But they had a fun 6dB boost in low bass...  :rofl:

Whenever I put a loud, clear cone speaker in this room a midrange spike appears in the room acoustic. It is really singing now with no treatments on the walls. I am pretty sure it just the room though. It feels different in my head than the speaker sound does, must be the arrival time difference. Anyway, there is a lot of acoustic treatment up on deck next. I am looking forward to that because it is easy work. But I have 100 degree weather all week! The speakers put too much energy into the room without room damping. It's getting very damped in here! At least 160 sq feet, if not 250+ if I have the time. It has to look good so that goes a little slower.

Still remaining to do on these speakers is proper feet, which elevate the bottom of the speaker off the floor to allow the internal horn to exhaust past the edges. I have been using a loose stack of 3 square blocks at each corner. That has been inconvenient to say the least in the tuning where the speaker was laid over numerous times. I guess I should have done the feet first, but still not sure how I want them to look or function. Blocks will remain until I figure it out. I will need solid footing in place before the witch doctor Carlman can come over here and put his magic voodoo on the positioning.

Wood finishing is all that remains. I plan to do a nice rosewood oil stain and satin urethane from General Finishes. It has worked well for me before without spraying or a booth.
Title: Re: DTQWT-12
Post by: richidoo on July 19, 2011, 03:10:38 PM
Actually, with a little more listening, I think I will pull out some stuffing in midrange horn, because the midrange is too subdued now, too soft SPL and too controlled and dry . It's a fine line because it can easily ring, so I'll be adjusting one cotton ball at a time here soon...  :roll:  But it will be great if I can find that balance of aliveness and control. It's a never ending tedious process, but so much better now than when I started. If the speaker weren't such high resolution the tuning would not be so critical. I am happy with the bass now, which is a relief!
Title: Re: DTQWT-12
Post by: Face on July 20, 2011, 07:44:00 AM
I'm really surprised the mid doesn't have it's own sub enclosure. 

As for feet: http://www.myesound.com/Points_n_pads.html
Title: Re: DTQWT-12
Post by: richidoo on July 20, 2011, 07:53:02 AM
It's a rear horn on the mid, supposedly interacts beneficially with the horn for woofers. Thanks for the link, those look nice!
Title: Re: DTQWT-12
Post by: eleazar on July 20, 2011, 11:33:25 AM
Parts Express black speaker spike .41 each when you by at least 4

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=249-727&FTR=249-727
Title: Re: DTQWT-12
Post by: hometheaterdoc on July 20, 2011, 11:39:43 AM
Rich,

I have at least a dozen sets of these here at the house:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=240-717

How high do they need to get the horn up off the floor?  These are 1.5" high without the cups....

I was going to post them for sale as I found a whole box full of brand new sets of these... I've used them for years on my custom subwoofers... really nice stuff....
Title: Re: DTQWT-12
Post by: Carlman on July 20, 2011, 11:41:28 AM
I highly recommend a permanently mounted, simple round foot with carpet gliders on the bottom.  
I would suggest you also find a place along the bottom of the speaker to additionally mount spikes with large knurled knobs that you could screw down into the carpet once you've decided on a location.  Then you can hear the difference in real time going from platform feet to spike feet... and have absolute control on all aspects of positioning.  I don't know why this isn't done as common practice...  :-k

What would be really cool is big round feet with large knob-rings incorporated with gearing to make it super easy.  Spring loaded spikes would also work... or flip-down spikes that are hinged somehow... Anything so that once it's in place, going spikes isn't a big deal... Because positioning with spikes is a huge time suck.

-C
Title: Re: DTQWT-12
Post by: richidoo on July 20, 2011, 12:12:23 PM
Thanks for the suggestions guys!

I want it to slide on the carpet for easy placement and position experiments, be easily picked up on the hand truck, and it has to have a 2.25" tall gap all around the bottom to allow horn exhaust.  So it will be a bottom plate the same size as speaker sitting on the floor, with the speaker suspended above it with matching veneer plywood risers. Some absorption on top of the plate to kill midrange echos in the horn as would carpet.

Some really nice footers over at Herbies Audio labs...
http://herbiesaudiolab.net/spkrfeet.htm
Title: Re: DTQWT-12
Post by: tmazz on July 20, 2011, 12:22:38 PM
Parts Express black speaker spike .41 each when you by at least 4

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=249-727&FTR=249-727

Wow! This web page makes a big deal about offering free lifetime technical support for you spikes!  :roll:

Talk about giving people the sleeves out of you vest.  :lol:

BTW: Anybody running a VPI HW-19 series table - the rubber feet on the bottom of the table are mounted using 1/2 - 20 threads, so these should fit right in as a direct replacement. I thought that coupling the TT to the counter-top with spikes was a very worthwhile improvement and I paid a lot more than 41 cents for mine. (Warning - if you have a non-American built TT remember that it most likely uses metric threads and these may not work for you. Search under speaker spikes and they have other ones with metric threads.)
Title: Re: DTQWT-12
Post by: richidoo on July 21, 2011, 08:03:22 AM
I removed a lot of stuffing from the midrange driver last night and that opened up nicely. I think it is just right now. No obvious ringing but a little bit of thickness. Good as it's gonna get. Quite beautiful actually.

The bass sounds good, no ringing, but extension is less than before, and softer than the midrange. So I need to remove some from the bottom of the bass horn (again,) to allow the full length of the horn to work to extend the bass as deep as possible. With the bottom of the horn stuffed full, the sound can't get in there and the bass extension is lost. Leaving a center path to the bottom unstuffed extends the bass while controlling ringing pretty well.

I am realizing that this is a horn speaker, so there will be a sonorous, bigger than life character to it. It is a beautiful sound, but not perfectly accurate. Sounds is fattened when amplified by the rear horn. Trying to make it a clean hifi speaker ruins the magic. So now after hearing it as hifi speaker I am backing off the damping to allow it to sing more, even though the tone is wettened enough to annoy an audiophile. The alternative is too dry for a music lover. Like any speaker, there is a compromise point in the damping between not enough and too much. Getting that correct is really important with a horn, and with horns this big the slightest change is audible and can make or break the speaker. Another aspect of the tuning is that the stuffing not only controls the ringing, but also the SPL. Since this speaker has two horns, the ringing must be controlled in each for different frequency ranges, but also the level balance between Mid and Bass also has to be right. Right now the mid is at optimal tone, and bass tone is good, but extension is limited and SPL too soft. So less stuffing will increase SPL and extension but the sound will become rounder and tonally less perfect, but more beautiful.

But it is soo much better now than the first listen, after half dozen changes to stuffing. One thing is good, my back doesn't hurt anymore from lifting these things, so I guess I needed some more back strength.

I want to weigh these speakers.  I have a bathroom floor scale, but I can't lift the speaker and place it gently on the scale.  Can I weigh the front edge while the rear edge is held up level to the front with some wood blocks, then do the same for the rear edge, then add the two weights together?
Title: Re: DTQWT-12
Post by: BobM on July 21, 2011, 08:30:17 AM
As the bass extends and opens up you will probably have to adjust the midrange and maybe the tweeter again. I've found that adding bass somehow always seems to make the top end more pleasurable and exciting too.

Dry sound is not enjoyable to my ears either. Music needs life and drama and dynamics, even at low volumes. It's all relative, but too much leads to fatigue. A balancing act for sure - I'm sure you'll keep tweaking for some time to come. And don't be surprised if the finishing changes the sound somewhat also.

DIY projects like this never seem to be completely finished, since you know the intimate details of the speaker and can make minute adjustments and tweaks and hear the changes that each makes. It's all fun, but just don't think that you'll ever be "done".


Title: Re: DTQWT-12
Post by: richidoo on July 21, 2011, 02:53:28 PM
Great points Bob! Thanks. I agree with all of it, unfortunately!  :rofl: The benefit of commercial equipment for me is that the fear of fucking it up prevents tinkering! But even that I think has it's limits, once a DIYer, always a DIyer. I think I know enough now to be a danger to myself.  I am already thinking how I can mod some commercial speakers that I want to buy but don't even own yet! Sick!  Why buy speakers that need mods?  :duh

Well, I hope I am close the finish line with the first stage of stuffing. I've covered the full range from loose to tight sound, and back and forth with the Mid vs bass interactions, so I am learning how much to take out and put in to affect the desired change. In the beginning it was just a crapshoot, steep learning curve, and sore back. It still takes a good hour to change the stuffing. You are right, opening up the bass will change the mid too. But the problem I had with mid ringing was up in the 800-1200 area. Certainly the woofers do play up that high also, but I don't have any of that midrange ringing now, so hopefully it will stay gone as I remove stuff only from the low freq part of the bass horn. In the beginning I did hear the midrange going over into the bass horn and ringing in there, a terrible cardboard box type coloring. The bass horn needs a little bit of stuffing all the way up to the top for that reason, to keep the mid from ringing up there.

I've been listening to the mids for 24 hours and this is the first time since startup that I have not heard anything I wanted to change with the mid sound. Open but not too colored, just a tad round as expected.  The designer mentioned in his OB11 design article that the OB design might be even better than his beloved DTQWT boxes for the less color and snappier 15" OB bass, I can see how that would be true. Eventually I'll build that OB11 also.

Tuning the speakers with Sol's i60 has been a great tool. It does not color anything and has plenty of extra power and bass grip. Switching to the 300Bs adds the tube charm which hides a lot of flaws. Better to tune it with a clean amp then enjoy an optimized speaker with the sexy amp later. I have enjoyed a lot of music with the i60s on these speakers too, especially when they are stuffed on the loose side.
Title: Re: DTQWT-12
Post by: richidoo on August 02, 2011, 07:46:10 PM
At the g2g, somebody connected the speaker wire bananas to the speakers in the normal way, speaker wires to bass posts and the bass posts are jumpered to the mid posts. I usually put speaker wire ground on bass and signal to the mid posts and jumper back to the other. This sounded better on my previous speakers. After the meet I noticed how nice the speakers sounded. Today I noticed the wires were normal, so I put them back to my weird way. Tonight listening to some great vocal tracks that Shane brought to the meet I started noticing that the mids were too soft (again.) Depressed that the nice sound of the previous couple days had been a cruel trick, I started thinking about pulling out stuffing, etc, to bring mids forward more. Then I remembered I'd moved the jumpers. So I just put them backto the normal way and the midrange came into balance. I think is it because the rear bass drivers play up very high and are more sensitive than the front drivers. So connecting SCs  to bass terminals reduced resistance and increased voltage to the bass drivers and brought out the mids.

Could also be that the tweeter is still a little too hot.  I think the treble sounds pretty good now, but worth trying another notch down. It was really too loud at the beginning of the g2g so I took it down .5ohms on Shane's advice and with his help. After the mod, he thought it could use still more attenuation.

I think I will try soldering jumpers internally at the crossovers to eliminate the external jumpers which don't really fit well on these cheapo Dayton style posts that came with the kit.  The inner post that must fit inside the spade is too fat to accept the spade. So I am clamping it as best I can, but it's not right. Jumpering at the crossover will eliminate that, until I can get some WBT posts.
Title: Re: DTQWT-12
Post by: tmazz on August 02, 2011, 08:33:34 PM
.... The inner post that must fit inside the spade is too fat to accept the spade. So I am clamping it as best I can, but it's not right.

I always keep a few sets of Monster X-terminators laying around for just such a situation.

(http://i66.photobucket.com/albums/h263/wwfactor/xterminator2.jpg)

The spades get tightened down on the x-terminator and then locked in with a set screw and the banana itself has a center pin which when screwed in spreads the blades of the banana insuring a tight connection. In addition to making nice adapters for binding posts that will not accommodate certain spades, they are also very handy at G2Gs because the make moving SC from amp to amp a very quick and simple job.
Title: Re: DTQWT-12
Post by: stereofool on August 03, 2011, 03:38:35 AM
At the g2g, somebody connected the speaker wire bananas to the speakers in the normal way, speaker wires to bass posts

GUILTY  :twisted:
Title: Re: DTQWT-12
Post by: richidoo on August 03, 2011, 06:18:01 AM
Thanks Tom, those would work nicely!
Title: Re: DTQWT-12
Post by: Face on August 03, 2011, 06:31:47 AM
Lose the PE posts and brass(cheap) nanners.  If these are keepers, they deserve a pair of Cardas posts. 
Title: Re: DTQWT-12
Post by: richidoo on August 03, 2011, 06:55:51 AM
You're absolutely right Face. I'm not sure they are keepers yet, hence the internal jumpers to bypass the cheap posts. I think I'll put the main input off of the PE posts too.
Title: Re: DTQWT-12
Post by: stereofool on August 03, 2011, 10:14:08 AM
As I mentioned Sat...put your crossover 'outboard' and it would be much easier to tweak  :pop!

Easy for me to say...I don't have to do all of that work  :rofl:!
Title: Re: DTQWT-12
Post by: richidoo on August 03, 2011, 10:56:03 AM
Converting to externals would be mighty pricey - to do it right, and I don't have any intention of using an active crossover on these. It's not too hard to work on the crossovers inside the big horn. I could always remove them easy enough, just two screws each.
Title: Re: DTQWT-12
Post by: lonewolfny42 on August 03, 2011, 03:06:56 PM
Quote
...says birth certificate...
  :rofl:
Title: Re: DTQWT-12
Post by: NorthBear on August 06, 2011, 03:33:56 AM
Hello Richiddoo,

First of all, sorry I d'ont speak English.
I live in the south of France. (La Couronne, near to Marseille)
I am interested about DTQWT-12
I would like to know if you're finally satisfied by your speakers DTQWT-12.
Many DIYers seem to have problems focusing with the bass.
According to their characteristics, they seem to have a sound that is closer to sono than HIFI, no!?


I can tell you with humility: there is four factors to be taken into account to reduce frequencies that pollute the sound:
 - The shape
- The mass
- Rigidity
- The volume

How to put this under?
I had some ideas.
What do you think?

Sincerely,
NorthBear
Title: Re: DTQWT-12
Post by: tmazz on August 06, 2011, 05:22:36 AM
Welcome aboard NorthBear.  :thumb:
Title: Re: DTQWT-12
Post by: richidoo on August 06, 2011, 06:49:12 AM
Hello NorthBear
You speak better English than I do French!  Thanks for posting about my speakers.

I am very happy with the DTQWT-12 so far. It may not show in these notes, because I am still focused on tuning them, and fixing problems that I overlooked before. I have not given my final review, which will be thorough, and positive, based on what has happened so far. 

I am listening to more music now with these speakers than I have in a long long time.  I think the acoustic damping of the internal horns is finished now, and I am happy with the compromise between less ringing and openness. I don't hear any objectionable ringing and I don't feel any stuffiness in the sound, this is with several different amps. It took about a dozen changes to arrive at this damping arrangement.

As for bass, I think you mean DIYers tend toward ringing horn than overstuffed. That is true, I think, because a ringing horn has drawbacks, but also allows the full extent of life and transient detail to come through. Overstuffing a horn to totally eliminate horn ringing also damps the back pressure on the cone and compresses it's transient response, so even the direct cone sound is lifeless and suffocated, just like in overdamped sealed speaker. But No damping makes the ringing overpower the direct sound, so some damping is required or it is even worse than too much.

I am interested in hearing about your 4 factors, please elaborate on each, if you care to.

For the DTQWT-12, the shape must be folded because to not fold the horns would make them 10 feet tall. I have 11 foot ceiling, so I was considering building them unfolded, but they sound good now so I will not bother. The shape of these horns is optimized using Martin King's Quarter Wave simulation software, which is the state of the art for horn design now. The horns could be improved by being unfolded and being conical rather than rectangular, but Troels designs for simplicity and economy to make it accessible for DIYers to build.

I don't believe that mass has any influence on the vibration of cainets other than to lower the resonant frequency, which makes damping more difficult. Carbon/foam carbon sandiwch is the ideal speaker building materials, very low mass, high stiffness, easy to damp.

Rigidity, yes, easy to damp. Same as stiffness. High mass materials like steel which are also stiff are good speaker materials, but are heavy, expensive and difficult to work compared to wood.

Volume is already optimized yb the Martin King software. I doubt it can be improved by listening and tweaking. The speakers designed with that software that I have heard have been excelent, this one no different.

I really hope that you will share your ideas and respond. Maybe you disagree with me, that is welcome and encouraged!
Thanks
Rich


Title: Re: DTQWT-12
Post by: tmazz on August 06, 2011, 08:33:39 AM
I am listening to more music now with these speakers than I have in a long long time. 

Rich I realize that the Nervosa in us wants to hear all the gory details about the performance, but that statement just about says it all.

I'm glad to hear you are enjoying them. You deserve to after all the hard work you put into this project.  :thumb:
Title: Re: DTQWT-12
Post by: richidoo on August 08, 2011, 01:30:02 PM
Thanks Tom! I am enjoying them, I missed them when I was away for the weekend.

Just found out that this same Audax TW034 tweeter was used in my Legacy Focus 2020s as mid tweeter, with a Japanese Foster planar ribbon tweeter above it. I bought a pair of these tweeters and 4 ribbons  as spares from the organ factory after they and Legacy parted ways. I gave them to the buyer of my Legacys. There are not many traditional soft dome tweeters with honest 93dB sensitivity. It's a nice sounding tweeter, although not extremely extended, which is fine with me. The DTQWT puts it into a waveguide to add more sensitivity.
Title: Re: DTQWT-12
Post by: NorthBear on August 09, 2011, 12:14:39 PM
Hello Richidoo,

I"am very happy''to try'' to speak with you.
But at the same time, I am frustrated because I am convinced that I would have serious difficulties to explain technical thinks.
First of all, I guess you have the share of your remarks Troels GRAVENSEN. What did - it recommended?
 

Let me tell you about a few of my accomplishments.
I speak you about my speakers because my son is torn between doing the same speakers that I, and the DTQWT ...
In my case, for the last pair of speakers that I realized, I opted for a minimalist filter, a heavy material, one side of the soundproofing of two components and elitist.
 

I realized hyper rigid boxes with 30 mm HDF (High Density Fiberboard, ± 1 000 kg / m³) I know this is not the top, but it was necessary that I exhaust my stock.
To improve things, I pasted lead plates that I also had in stock.

I selected the speakers and filtering components of exceptional quality. (Duelund Cast - Mundorf L300 30/10e)
 All supplies are non-magnetic annexes: Stainless steel A4 - Brass - Aluminum - Teflon.
 The welds were made with the son's silver / gold.

Therefore, we neglect the''bottle''.
Only one scene of drunkenness LIVE shows that the cost of the cabinet is fully justified.
 What strikes''from the first notes, it is the ventilation and transparency.
It seems that the sound does not come from boxes!
We hear endless details and the music is expressed with a clarity, a sharpness, a rare texture and depth.
 The scale of the scene is impressive. The spatial position and the truth of stamps of each instrument are met. The attacks are dazzling.
 A fan of Jazz d'Antibes said: We taste here in the magic of Live!''
 


True, the sound is faster in dense matter
However, contrary to the notions of common sense, we found that some rocks do not resonate, yet good quality: the most obvious case is that of dolomitic marbles, which give only a dull sound at impact.
A friend has reproduced my speakers, but with this type of marble.
The result is net!
More transparency.

I have attached some links to this post.
Open them and uses an electronic translator.
I think it's worth just tired. Anyway, I am inspired.
http://www.deparisnet.be/Bruit/faqbruit/faq_bruit3_materiaux.pdf
http://aboudet.chez-alice.fr/doc_musique/son-nature.html # mozTocId214443
http://www.petoindominique.fr/php/amortis.php
http://www.spectra.fr/mousse-acoustique-a18.html
http://www.jeanmaurer.ch/Produits/Jm-technologie/techno-e-boitiers.htm
http://www.roches-ornementales.com/Site-Resonance-long/RESONANCE-LONG.HTML

So, tell me if you have managed to profit from it.

I enjoy to read you,
NorthBear

N.B. Is it possible to attach a photo?
Title: Re: DTQWT-12
Post by: richidoo on August 09, 2011, 12:27:13 PM
Merci Northbear

I am reading your post and enjoying the photos. I will reply soon.

In the Meantime, you may attach pictures using the link "Additional Options..."
Title: Re: DTQWT-12
Post by: richidoo on August 09, 2011, 12:53:07 PM
Good links, thanks!

I understand your message to say that your son is trying to decide to build DTQWT or a speaker that you have already built. It sounds to me like your own speaker design is very refined perfectionist and expensive.

The DTQWT is not a perfectionist speaker. It's compromises allow music lovers to find their satisfaction while using low wattage single ended triode amplifiers. Audiophiles seeking perfect transient response of a sealed cabinet and perfect coherence of phase linear crossovers will not find that here. But it is efficient, sensitive, musical, and cheap to build using the Jantzen kit. Minor cabinet resonance and some horn ringing is part of the lovely sound. Technical performance is more than adequate to enjoy all kinds of music at high and low volume. They sound like high end speakers, on the warm and forgiving side.  I would not call them audiophile speakers, but music lovers' speakers. :D

Troels Gravesen diy designs are intended for DIY constructors on a budget who want quality sound and high value. Of course his designs can be modified to perfectionist standards if the budget allows. I damped the interior surfaces with heavy roofing bitumen. That, along with the bracing described in the plans controls the cabinet resonances well. The internal pressureis minimal and the Mms is low, as is excusion at highest volumes. So there is very low source of vibration. Cabinet coloration is minimal with the recommended bracing and damping. Maybe I am wrong and less cabinet resonance would help, but it is already too heavy and I am bored of more mods.

First of all, I guess you have the share of your remarks Troels GRAVENSEN. What did - it recommended?

Sorry, I don't understand that. Try again?
Title: Re: DTQWT-12
Post by: richidoo on August 09, 2011, 03:48:54 PM
I was curious how the mid and tweeters would sound alone, since there is a TQWT version, with no woofers. I disconnected the jumpers and moved the bananas up to the MT posts. Nice, not bad at all. Only a little bit of horn color, very musical, but tillted up without the bass to balance.

Then I moved the SCs to the bass drivers only. Midrange melodies are audible, and the horn sounds slow, considering how much midrange is coming out. I know that bass is slow, but speeds up when mids and upper mids are added. Upper mids are pretty well attenuated from the woofers.

Then I reconnected the JPS jumpers. They don't fit well, because they are intended for 1/4" post, while these posts have a bigger post. So the jumper tongues are wrapped around the post at the narrower part where the bare wire hole goes through the post. The jumpers don't sit flat on the base of the post, but are tightened down pretty good against the nut. Still a lousy connection, since the majority of current must pass through gold plated brass nut threads to get into the post, which is then bolted to the tab washer inside.

Anyway, with newly tightened jumpers, the overall quality of sound improved noticeably. Even bass started to have that open, floating airiness. So these posts/jumpers are definitely a problem. I'll solder the crossover inputs together and use a set of different posts that I have on hand, still Dayton, but much better. I can't put $300 into super posts and spades.

I found this sales blurb interesting, especially about the clunky junk metal posts smearing the bass.
http://www.vhaudio.com/cablepod.html
Title: Re: DTQWT-12
Post by: Face on August 09, 2011, 06:20:40 PM
All you need: http://soniccraft.com/products/connections/bindingpost/cardas_ccgg.htm and http://soniccraft.com/products/connections/spade/vampire.htm or http://soniccraft.com/products/connections/banana/vampire_b12.htm
Title: Re: DTQWT-12
Post by: richidoo on August 09, 2011, 08:13:09 PM
Thanks Face, for nudging me... ;)

I like the new avatar, I guess you finished them?
Title: Re: DTQWT-12
Post by: Face on August 10, 2011, 06:11:41 AM
Nope, moved onto something else, a 3 way bookshelf with a pair of Anarchy Woofers, Scanspeak mid and tweeter per cabinet.  I plan on finishing the BB speakers by the end of the year though. 
Title: Re: DTQWT-12
Post by: richidoo on August 10, 2011, 06:44:30 AM
 :thumb:
Title: Re: DTQWT-12
Post by: NorthBear on August 13, 2011, 03:54:37 AM
Richidoo,

I send you onr image of my speakers

NorthBear
Title: Re: DTQWT-12
Post by: NorthBear on August 13, 2011, 04:09:37 AM
Richdoo,

Thank you for your opinion and your deductible, while you describe your speakers


In the Meantime, you may attach pictures using the link "Additional Options..."Is
Do you recommanded to Troels GRAVENSEN? (Councils from him)

Read the following post: http://www.troelsgravesen.dk/download/TJL3W_Ingvar.pdf

''Following your advice on how to lower the level of the midband (1 ohm before the mid crossover and 47 ohm across its terminals) I must say the sonic result fulfills all my expectations. The treble, mid and bass are now wonderfully smooth integrated. The bass is clean and fast, articulate and deep. Overall, the sound is transparent and convincing. Ben Webster’s tenor sax has never sounded warmer and more full-bodied to me from a pair of loudspeakers and I have never heard any loudspeaker reproduction of classical music more sweet and seductive. So thank you for inspiring me to build these wonderfully sounding speakers.
Kind Regards
Ingvar Bergman/Stockholm''


@+
NorthBear
Title: Re: DTQWT-12
Post by: richidoo on August 13, 2011, 07:30:56 AM
I have emailed with Troels about my speakers and he has posted a link to this thread from his website. His advice is very helpful. He provides excellent support to the builders of his kits.

Today I will finally be able to fix the posts and the tweeter.  I decided to order the Eichmann speaker posts as they will allow me to use my bananas and they have no metal threads, but I might change my mind. ;)
Title: Re: DTQWT-12
Post by: NorthBear on August 14, 2011, 10:50:25 AM
Richidoo,

Have you seen my speakers on page 11?
Can you tell me the link where Troels advise you, please?

Best regards,
NorthBear
Title: Re: DTQWT-12
Post by: richidoo on August 14, 2011, 11:36:30 AM
Northbear, I'm sorry I did not see your speaker picture. Thanks for bumping it!  I like the color! Grape Ape
(http://1.bp.blogspot.com/_cqi-yDToJ7A/TTJFlGe2V-I/AAAAAAAAABY/5o2zKNyr0D4/s1600/grape-ape2.jpg)

It looks like low distortion SEAS drivers in large volume with reflex alignment, and no separate bass drivers. More midrange accuracy, better audiophile tricks, bass down to ~40Hz. I think my bass goes down to about 30Hz and it is loud and punchy. I still have to measure it, but I know that the speaker cable connections will affect the bass volume (and clarity) so it must wait until I get that fixed.

Troels advised me by 4 emails. I will post them here.
Title: Re: DTQWT-12
Post by: richidoo on August 14, 2011, 12:12:16 PM
Email response from Troels dated 7/22/11. His comments are in BOLD

-----------------------------------

Hi Troels
I have the DTQWT-12s finished. They play low and powerfully, as promised. The tone of the mid/tweeter is awesome, and everything I hoped for. Open and alive, tone is full and satisfying, yet sharp on brass and violins where needed. Gorgeous and exciting sound. I am using the largest 2.7R tweeter resistor. Solo violins never sounded better!  Congratulations on a great design. There is not quite enough tweeter for the showoff audiophile recordings like 2L, Chesky, Reference, but for real music it is perfect. I might install a switch to choose the tweeter settings for showing off. :)
I’m pleased to read your comments. Yes, sadly we need tone controls on our pre-amps. Many recordings can be improved by +/- half a decibel of treble or bass level.
Lennart (Sweden) brought his amps here a couple of months ago and the tone controls were used extensively, in particular at low listening levels where bass needs a 1-2 dB boost on most recordings.

Mine have only 15 hours of playing so far, and have improved a lot from new. But more time is needed for the drivers and filters to burn in.  But I am hearing some resonance that is not changing and I am not sure whether it is break-in, acoustic damping or panel resonance. I have loosely packed acoustistuff line damping from the bottom of the rear bass horn up to the bottom edge of the bottom woofer, and the the front midrange horn is stuffed similarly, plus a small wads on the sides of the midrange up to height equal to the top edge of mid driver. I went light on the damping fluff because in previous projects I used too much and killed the life. Fortunately, this design allows adjustment after construction.

My question is about tone. I am getting a warm thick congested tonality from upper bass through the midrange, I would guess through the 100-800Hz range. I played the midrange/tweeter only with no woofers powered and still heard the excessive warmth to a lesser degree.  It seems like the very bottom two octaves up to 80Hz are pretty clear, but hard to tell for sure because I'm not sure what horn loaded bass should sound like, other than "good."  The distortion is worse with higher 90dB volume levels. At normal soft levels 80dB the resonance is not too bad, but midrange and upper bass tonality is still pretty colored.
Well, this is really hard to comment on without hearing and in particular measuring panels resonances.
You damping work sounds good and appears what I would do.


The cabinet is constructed of decent quality 18mm hardwood plywood, and front baffle is 2 layers 36mm. The mid section of the front baffle is made of strips of plywood turned on edge and laminated together for extra stiffness. Internal bracing matches your drawing. The entire inside of the speaker is lined with heavy (4kg/ m^2) rubberized bitumen. 10mm felt is applied over the bitumen in locations recommended in DTQWT.

Building saga and pictures unfolded here: http://www.audionervosa.com/index.php?topic=3070.msg
Looks impressive and I suggest trying this: If you have two large panels of e.g. 20-22 mm, add these to the sides and fasten with (lot of) clamps to hear if anything happens to the sound.
Next, the rear panel may not be the most rigid seen. 2 x 18 mm might have done well here. Hard to try out things here to hear if things may improve from thicker panels.
I would have used the same for rear as for front carrying two heavy 12” drivers.


Any suggestions how to improve the tonal clarity? I can thicken the exterior and/or add more stuffing, but I'm not sure which one to attack first.
Try out side panels first.
I'm hoping you are familiar with this problem from tuning DTQWT. Maybe the guy from Italy can reveal his stuffing or bracing secrets if he made it play cleanly. I know he used laminated baltic birch which is much stiffer. So if he had no resonance problem then I know I need to stiffen the panels. Can you send him my email address?
I’ll forward you mail to Ferraioli.
best regards
Troels


--------------------------

In retrospect, my questions were written to Troels soon after completing the construction. The drivers have continued to burn in since then, until just a few weeks ago, improving all the time, especially bass clarity. I have also changed the stuffing about a dozen times since then, which has cured almost all of the ringing problems. Also, the speaker posts that come with the kit do not fit my JPS jumpers, so the jumpers were connected poorly, which really affected the sound in a negative way. That will be fully fixed with single Eichmann speaker posts per speaker and internal wiring to both crossovers, no jumpers. I will never biwire this speaker. Jantzen sent dual posts for free because I requested satin nickel finish but they were out of stock. I only wanted satin nickel because my wife ordered satin nickel hardware with our new house, and I wanted to give her a sarcastic nod. She could care less the color of the speaker posts. But then I made the mistake of using both pairs per speaker instead of just soldering the crossovers together for best connection. These speakers are intended to glorify SET tube amps, so the idea of putting SS amp on the bass and SET on the treble is heresy, and never works anyway, on any speaker it's tried. Vertical biamping should be the same amps, imo.

I am not yet ready to give final review of the sound, so you DTQWT12 prowlers don't read too deeply into my passing comments about sound quality during the tweaking process. They are written only to share with my AN friends "the thrill of victory and agony of defeat" (http://www.youtube.com/watch?v=P2AZH4FeGsc) through the process.

This is DIY, and I am an amateur builder. It is not to be expected that the speaker which even the designer never built or heard for himself just pops together into perfect tuning on the first try. Good commercial speakers take years to perfect, but there is no daily blog to scare away potential customers during the agony of defeats!

When I feel that I have squeezed all that I can from this design I will have another listening party and get more feedback. Then more changes, hopefully small and then I'll be close to the end. Unless I decide to build another sturdier and better damped cabinet for them.

Eventually I will write a review and summarize my experiences and the specific thiings I learned to help future builders. But they will not want it to sound just like mine, so they will still need to tweak their own.
Rich
Title: Re: DTQWT-12
Post by: richidoo on August 14, 2011, 12:34:52 PM
Email 2: Troels just writing to say he could not find Ferarrioli's email address, and to have a fun time at the upcoming meet.

----------------------------------

Email 3:
Hi again,
 
Looking at the photos, I wondered if the 8008 is completely sealed off towards the center horn?

(http://www.audionervosa.com/MGalleryItem.php?id=922)  (http://www.audionervosa.com/MGalleryItem.php?id=923)

As can be seen on drawing, there is a piece of MDF panel sealing off the hole for the magnet.
If not completely sealed, the 8008 will not load the front horn properly and you may just glue two pieces of MDF to the front internal panel and the bracing.
There must be some distance from the magnet hole to the additional sealing panel in order to allow proper ventilation from the voice coil and dust cap cavity, preferably 10-15 mm and there should be some damping material behind the magnet too.
I guess I have to specify this more clearly.
 
best regards
Troels


I replied that the picture was of unglued parts layout. The hole is sealed with 1/8" masonite damped with 1/8" bitumen and a brace.  The hole was not stuffed with fluff though, so I added that.  It might have been a part of the changes that improved the sound since then. But I did not compare before and after I damped the mid driver vent.

------------------------------------

Email 4: Troels just acknowledging my reply that the hole is sealed.

--------------------------------

Tuning the horns is the main chore after building, and is the make or break factor in the sound. IMO, the cabinets are sufficiently braced and damped for this speaker's role, music listening with low power amps at moderate levels. But I don't hear any noticeable cabinet resonance even at high volumes that I can hear are pushing the midrange out of its comfort range - really loud. As for the rear panel, The rear drivers have aluminum frames screwed to the rear panel and grounded mechanically to the immovable perpendicular sidewalls. With that, there is NO significant mechanical vibration of the rear panel possible due to driver vibration. Further, the rear drivers are braced immediately below, between and immediately above the woofers. Acoustic pressure movement is possible in the bottom half of the horn below the 10" tall brace, but these drivers hardly move, that part of the horn is well stuffed, and the horn is expanding exhaust type so pressure wave energy mostly moves toward the exit so pressure fluctuations are really not an issue on the rear panel. Higher frequency resonance is damped with bitumen on all interior surfaces of the rear horn.
Title: Re: DTQWT-12
Post by: NorthBear on August 14, 2011, 01:37:06 PM
Richidoo,

I have not read everything carefully, but it seems  councils's Troels are similar to those of John  MAUER:
http://www.jeanmaurer.ch/Produits/Jm-technologie/techno-e-boitiers.htm
I'll read carefully and I contact you.

Give me your adress e-mail and I'll give you adresses of FERRAIOLI Pantaleone:   

@+
NorthBear  (Thanks for "my photo" !)
Title: Re: DTQWT-12
Post by: richidoo on August 14, 2011, 01:54:25 PM
Please invite Ferraioli to our little space here, and he can join us if he is still interested in the DTWT-12. Do you know if he still uses it? As far as I know he is the only other builder, but I could be wrong. I think it must sound great with his 50W Mastersound 845 amps.

Thanks
Rich
Title: Re: DTQWT-12
Post by: NorthBear on August 14, 2011, 02:01:52 PM
Richidoo,

Ok, I'll contact him.
Neodym Eminence DELTALITE®-II 2512
Usable Frequency Range  48Hz-4kHz
http://www.toutlehautparleur.com/deltalite/eminence-deltalite-ii-2512-p-3178.html

SEAS W21EX001
RECOMMENDED FREQUENCY RANGE 30-3000 Hz
VAS 63.8 Litres
http://www.toutlehautparleur.com/woofers/seas-w21ex001-e0004-p-3072.html

Title: Re: DTQWT-12
Post by: NorthBear on August 14, 2011, 02:03:03 PM
Dynaudio Esotar T300D (See doc attached)
Nominal Impedance (Znom): 8 Ohm
Voice coil diameter (dc): 28mm
DC Resistance (Re): 5.2 Ohm
Voice coil height (hc): 2.8mm
Voice Coil Inductance (Le): 0.07 mH
Voice coil layers (nc): 2
Resonance Frequency (fs): 750 Hz
Magnetic gap height  (hg):
2.5mm
Mechanical Q Factor (Qms): 0.33
Linear excursion: 0.3mm (peak to peak)
Electrical Q Factor (Qes): 0.5 Max.
Excursion: 3.2mm (peak to peak)
Total Q Factor (Qts): 0.2
Magnet weight (wm): 0.7 kg
Mechanical Resistance (Rms): kg/s Power Handling
Moving Mass (incld. air load,Mms):0.45 g
Nominal long term IEC: 130W (crossover dependent)
Suspension Compliance (Cms): - mm/N Transient (10ms): 1000W
Effective Dome Diameter (d): 31.3 mm Mechanical Properties
Effective Piston Area (Sd): 7.7 cm squared
Net Weight: 1.6 kg
Equivalent Volume (Vas): - l Overall dimension: 140.1 mm diameter x 66mm
Force Factor (Bl): 4.6 Tm
Recommended Frequency Range: 2000 – 30000 Hz
Overal Dimension: diameter: 140 x 66
90 dB sensivity  2.83V 20 - 200 watts continuous power handling.
 
http://www.gattiweb.com/dynaudio.html
Title: Re: DTQWT-12
Post by: NorthBear on August 14, 2011, 02:08:19 PM
Richidoo,

I've to send an e-mail to Leo (DTQWT-12)
Probably he join us !

Now I'll go to bed!
NorthBear
Title: Re: DTQWT-12
Post by: richidoo on August 14, 2011, 02:22:25 PM
Thanks Northbear. Good night

Why did you post the specs of your drivers in the DQTWT-12 thread? 
Title: Re: DTQWT-12
Post by: richidoo on August 14, 2011, 07:35:36 PM
I spent about 3 hours tonite with my hand jammed down into the bass horns to remove the 8 Dayton chinese crap speaker posts. When I installed them I did measure the distance to the closest woofer hole to make sure that my arm was long enough in case I had to access them, but didn't think it would be this quick! The bitumen has sand on the surface so it did a number on my hands.

Then I soldered the upper drivers' crossover input to the input of the bass crossover in parallel. Then I used a Radio Shack dual speaker post to connect the crossover input bare wires to the cables. So it is a much better connection now, no screw threads in the signal path, no washer tabs, no jumpers.

While I was in there I found the nuts holding the washer tab ring lugs not as tight as they were when I installed them. They can't take much torque or the thread strip, on either the shaft or the nut, I did both during install. I don't think they are even brass, they seem like whiter color base metal under the gold. These posts are definitely not good enough for a Jantzen kit when every other part is so great.

I also increased the tweeter resistor by another 1/2 ohm, to 3.7 now. It is better,  but it can still take even more pad. I will use two of the included Jantzen resistors 1.8 + 2.2 in series to bump it up to 4 ohms. It's funny, when you have too much treble, the detail becomes annoying and you block it out. As the treble level comes down into balance, you can relax and listen deeper and the detail seems to improve. A shoutyness around the crossover frequency also seems to be lessened by bigger pad, but still a little more to go there too.

I found some errant fluff in the bottom of one bass horn, I guess I didn't sort it carefully enough last time I was in there.

With all that, plus lasering the tweeters to perfect distance within 1/16" I sat down to listen to my audiophile test tracks playlist. I was pretty impressed with the overall improvement. It sounds much more audiophile-ish now. Bass is clearer. Midrange is much more intense and dense than before. That plus the eased off tweeters is bringing out a bit of an exciting musical personality. Hopefully more of that will emerge.

Imaging is improved a little. I think it will improve more when I round the sharp cabinet edges near the tweeter.

At very high volume there is still some high Q resonant midrange frequencies in the main center horn, 400-800, so that needs to be fixed. And there is still a bit of low mid resonance too, in certain places. So I hope I can improve those further. But at normal levels it is not a problem.

Overall a successful mission.
Title: Re: DTQWT-12
Post by: NorthBear on August 15, 2011, 11:23:32 PM
Richidoo,

Why did you post the specs of your drivers in the DQTWT-12 thread?
It looks like low distortion SEAS drivers in large volume with reflex alignment, and no separate bass drivers. More midrange accuracy, better audiophile tricks, bass down to ~40Hz.
I think my bass goes down to about 30Hz and it is loud and punchy.
I go down to 33 Hz with SEAS and I cut the DYNAUDIO to 2000Hz!
You tell me how much you go down with DTQWT.

 As for the benefit of the mass, look at the SONUS FABER 3 / 4 on the following page:
http://www.magazine-audio.com/2011/munich-high-end-audio-2011-part-2/
 They including 304 kilograms and cost ... 14 000 euros!
Title: Re: DTQWT-12
Post by: NorthBear on August 15, 2011, 11:51:38 PM
Richidoo,

Have you seen the speaker or ELIPSON or ETHER?
They were plaster ...
See the following document to understand the advantage of this material:
http://ww2.ac-poitiers.fr/techno/IMG/pdf/Sequence_4_synthese_Materiaux.pdf
Title: Re: DTQWT-12
Post by: richidoo on August 18, 2011, 07:48:18 AM
Let's stay on topic with this DTQWT-12 discussion. Thanks! 

A couple days off for another trip out of town and coming back with fresh ears I am still getting too much treble, even down to low treble at the crossover. Brass are a little too brassy. So I'll pad it down some more til I find the right level.  I am at 3.7ohms now. 4.5 next.
Title: Re: DTQWT-12
Post by: richidoo on August 18, 2011, 12:42:05 PM
The improved speaker connections have really transformed the bass clarity and overall dynamics. I think some of the problems I had at first which I blamed on not enough stuffing were due to poor connections which raised the source impedance of the amp thus sacrificing control. I am listening to Rite of Spring, and I can hear the individual oscillations of the bass violins in the beginning. Great low bass texture, aka "fast and dry" just as Troels described.
Title: Re: DTQWT-12
Post by: NorthBear on August 28, 2011, 11:31:20 AM
Richidoo,

Je suis trés content pour toi quee tu sois satisfait.
Si j'ai bien compris, la quantité d'insonorisant n'a pas été la solution.
Les résultats obtenus, peux-tu me les montrer en photos s'il te plaît?
Je ne sais pas si finalement ce que je t'avais dit a une importance capitale pour la transparence du son et notamment la qualité des basses.
J'ai obtenu d'excellents résultats au niveau des woofers avec:
Des selfs TRANSPARENTES:
http://www.toutlehautparleur.com/bobines-zero-ohm-n250-c-203_374_461.html

De la soudure argent, comme dit précédemment:
http://www.toutlehautparleur.com/soudure/mundorf-msolsg-p-2455.html

En soudant tous les composants directement entre eux.
En utlisant des borniers de qualité et des fils 650 brins.

La différence est Ahurissante!

NorthBear
Title: Re: DTQWT-12
Post by: richidoo on August 28, 2011, 04:09:58 PM
Translated by google:
Richidoo,

I am very happy for you quee you to be satisfied.
As I understand, the amount of soundproofing was not the solution.
The results, can you show me in pictures please?
I do not know ultimately what I told you was crucial to the transparency of its particularly low quality.
I got excellent results at the woofers with:
Chokes TRANSPARENT:
http://www.toutlehautparleur.com/bobines-zero-ohm-n250-c-203_374_461.html

Weld money, as said before:
http://www.toutlehautparleur.com/soudure/mundorf-msolsg-p-2455.html

By soldering all the components directly to each other.
Played in high quality terminal blocks and 650 strands son.

The difference is amazing!

NorthBear

Thanks Northbear for the good information.

The acoustic damping (stuffing) quantity and placement are both critical. After many experiments and listening I found the right recipe. I cannot take pictures because it is inside the cabinet.  But I can describe it in words.

Bass horn: Acoustistuff 3 inches thick against the sidewalls from bottom of horn to the top of inner horn wall. http://partsexpress.com   Leave the center passage open for best dynamics and deep bass extension.

Midrange horn, similar to above, with 2" thick lightly fluffed acoustistuff along the sidewalls as far down into the horn as possible, and about 8" above the center of the midrange driver.

Use a blob of light fluff behind the midrange driver between the vent hole and the horn wall.

I used Cardas Quad Eutectic Solder for the crossover assembly. It is not silver, but it works well. When it is finished I will switch to Wonder Solder. http://www.trt-wonder.com/

After improving the speaker cable to speaker connection and optimizing the stuffing I am now satisfied with the performance of the bass. It sounds clear, and is punchy and extends very low, so improving the quality of the bass coil is not necessary, although I know there are always better parts. :D  I will remember those you linked for future projects.

These crossovers are point to point construction using the provided terminal blocks which are not in circuit.
Rich
Title: Re: DTQWT-12
Post by: NorthBear on August 29, 2011, 09:01:02 AM
Rich.,

Thank you for recapitulation and to have took time to make me read the mail Troels.
If you wish, I could send you a document I had prepared on the construction of DTQWT-12
Cost: € 3200
I am planning a huge sound with a medium warm and voices forward.
I have a vintage amplifier SA200 & C200  AR Cambridge.
And a reader CD 723 Philips modified, Able to ignite other materials over € 2500.
I must say what to put there too.
Are you interested to receive this document ?...


NorthBear
Title: Re: DTQWT-12
Post by: richidoo on August 29, 2011, 09:53:50 AM
Please link to your document in this thread for all to see.

€3200 is triple the cost of mine. Why is yours so expensive?
Title: Re: DTQWT-12
Post by: NorthBear on August 30, 2011, 11:32:55 AM
 Richidoo,

I’ll link my document soon.

Why is yours so expensive?
Take account in what I’ll tell you now,   I included it in my future realization of DTQWT-12:

I try to optimize the quality of DRIVERS that I selected.    
It is only my opinion, but better to choose a MOREL ET 338-137 € or AUDAX Two34X0, like yours…,
► with a capacitor-Mundorf M-CAP SUPREME SILVER / GOLD / OIL 1200Vdc 5.60 uF to 146 € http://www.lautsprechershop.de/hifi/cond_mun_fr.htm
http://www.lautsprechershop.de/pdf/morel/chassis/et338.pdf
http://www.toutlehautparleur.com/audax/audax-tw034x0-p-1804.html


Than a Dynaudio T330D ESOTAR to € 1400
► With Capacitors Mundorf audiophile 400VDC 5.60μF MKP MCap to 5.13 €
Not even a Jantzen Z-Superior MKP to € 23.05
http://www.toutlehautparleur.com/mcap-mkp-400v/mundorf-mcap400-560-p-4058.html
http://www.lautsprechershop.de/

To my point of view, this is nonsense!

Ditto for the terminal blocks, cables (651 bits) and the quality of welds.
This must be beyond reproach and consistent.
Finally, the box should have walls of 40 mm minimum and reinforcements smart!

About boxes, at the risk of repeating myself, DEAF materials are an essential basis for high quality speakers for restitution.
(The famous principle MASS / SPRING)
  
36 years ago, an engineer friend had used a flow line from concrete storm of Public Works. That's why I mentioned the other day speakers ELIPSON plaster with hemp tow
http://www.cerib.com/uploaded_files/basedoc/1132741572_tuyaux.pdf
Indeed, they were huge (very big) !
But I kept this moment only a musical "emotional memory":
A huge sound and transparency rather striking.
What I can say is that at the time I had already several HIFI, best, and yet his coveted stuff!
He worked in military surveillance. And the components were so ... military grade.

Today, there are woven polypropylene binders and adapted to the characteristics of concrete.
 We can cut and masonry at will!
Make shapes like SONUS FABER ... possible while retaining a useful litrage (volume) adapted.

From the building, there are also soundproof, pure wool.
Plates 1200 x 60 x 100 mm, the acoustic performance and very interesting price.
 Honestly, I think value for money (for those who can not afford the Baltic Birtch or dolomitic marble) it must be .... CONCRETE (béton)!
  
I recommend also the location of CROSSOVER into the heads of speakers in a sealed boxes and a vibration-proof plate.
The capacitors are very sensitive and restitution is affected!

These are some principles, based on experience that have been approached in my choice for DTQWT-12.
Title: Re: DTQWT-12
Post by: richidoo on August 30, 2011, 12:44:06 PM
That sounds like a fun adventure. I look forward to reading about your build and the final result.

Your english is getting BETTER!  :thumb:
Title: Re: DTQWT-12
Post by: Face on August 30, 2011, 12:59:40 PM
I recommend also the location of CROSSOVER into the heads of speakers in a sealed boxes and a vibration-proof plate.
The capacitors are very sensitive and restitution is affected!
You mean sensitive to resonances.  ;) 

I agree, but going external would be even better.  Another option would be to pot the crossovers in a brick of resin like Wilson and Sonus Faber. 
Title: Re: DTQWT-12
Post by: NorthBear on September 03, 2011, 03:45:43 AM


I do'nt say you do !
I do it too.
We can hear the difference.
Title: Re: DTQWT-12
Post by: richidoo on November 06, 2011, 11:27:12 AM
Been fiddling with the speakers again, trying to optimize everything for the upcoming g2g.

I had placed about 3 sq feet of 703 FG insulation board into the center of the main horn to kill off a midrange peakiness that I heard during the stuffing process. It was a drastic measure taken in frustration with the sound of the new speakers. Over the ensuing months I realized that it made the speakers sound very muffled (duh). So for the g2g I was determined to kill off the muffled sound so I pulled out the FG and they really opened up a lot. I guess I didn't notice the muffling when I first put them in. I was pleased to discover that most of the midrange peakiness did not return with the FG boards removed, so win-win. I did some stuffing changes since I added the 703, but the smoother midrange is probably due to more burn in of drivers and caps. I'll try adding a bit of fluff behind the midrange driver to tame the remaining bite just a bit.  

But I gotta say that at the moment I'm very happy with the sound of the speakers. After I digest these changes I'm sure I'll hear the need for more adjustments, but it's a new high water mark.

I made some measurements before this latest change which show a good FR overall. I'll measure again after these final stuffing changes and post the curves.

I'm listening to my favorite symphonic band music (Fennel/Holst, etc) for a change, turned way up loud. No cringes! Bass drums like thunder crack, tone is pretty good except for the wily flutes, and dynamics are almost as good as my old Legacys. Very alive. This is with Sol's SS (120W) i60. More air (and noise) will come with the SETs.  I'm digging this!
Title: Re: DTQWT-12
Post by: richidoo on November 09, 2011, 04:40:58 AM
The midrange driver is making a slight upper midrange glare. I think it is from the breakup mode of the driver which is undoped paper. The FR of the driver up close shows the breakup bump, but it's peak is broad and relatively smooth and flat. The sum with tweeter looks great, damn near perfect sum. But there must be some uncontrolled resonance in the cone because upper piano and flutes are peaky and the overtones of lower notes glow too much, along with overall mid brightness. It is centered around 1200-1400 so it's not too annoying, but I'd like to try to make it better.  The acoustic response measured inside the horn mouth shows nothing at those freqs and steep dropoff -50dB at 1.5kHz so it's not acoustic resonance in the horn. I can block off the tweeter with my hand and it does not affect the problem.

So I want to try adjusting the midrange low pass filter. This is the schematic.
(http://www.troelsgravesen.dk/JA8008_files/TQWT-mkII_crossover_3.GIF)
It is a first order filter with the coil L2011. The coil is bypassed with what I would call a zobel filter to lower the coil's Q, which bends down the response. I want to steepen the bend, so I think I need to increase the size of C2011. Do you concur?

C2011 is only 1.0uF, so I'll parallel some smaller caps onto it.

I will measure before and after.
Thanks
Rich
Title: Re: DTQWT-12
Post by: richidoo on November 10, 2011, 11:18:03 AM
I tried parallel caps but it didn't work. The FR graph below shows acoustic response with mic inside the mid cone. The gold is the stock 1uF crossover cap. Caps added in parallel to make: Green is 1.22uF, Blue is 2uF, Red is 11uF. The red attenuates at 1.5kHz, but its 4 kHz increases.

(http://www.audionervosa.com/MGalleryItem.php?id=988)

I could not hear any difference. 
Title: Re: DTQWT-12
Post by: richidoo on November 10, 2011, 11:26:41 AM
In room frequency response, both speakers playing mono test signal, 1/3 octave smoothing. Not bad.  The tweeter is deliberately padded down more than the original design, and has natural early rolloff. 

(http://www.audionervosa.com/MGalleryItem.php?id=989)


Midrange / Tweeter, mic on axis 18" away, height centered between driver centers. Crossover is supposedly at 2kHz. Looks good!

(http://www.audionervosa.com/MGalleryItem.php?id=990)

Title: Re: DTQWT-12
Post by: richidoo on November 13, 2011, 10:39:29 AM
With the different tube amp the midrange issue has gone away. It must be amp related somehow, damping or whatever.
Title: Re: DTQWT-12
Post by: tmazz on November 13, 2011, 02:53:27 PM
With the different tube amp the midrange issue has gone away. It must be amp related somehow, damping or whatever.

Synergy, synergy, synergy.  :roll:
Title: Re: DTQWT-12
Post by: richidoo on November 13, 2011, 04:05:18 PM
Yes indeed Tom!
Title: Re: DTQWT-12
Post by: richidoo on November 22, 2011, 03:03:06 PM
Total Harmonic Distortion per frequency, 2.8V sine at the speaker, about a foot in front of the front drivers. This is very good. Higher voltages of 5.6 and 11.2 made same shape trace and staying under 1% at 11V except for the 900Hz bump. That's LOUD!

(http://www.audionervosa.com/MGalleryItem.php?id=1020)
Title: Re: DTQWT-12
Post by: richidoo on December 15, 2011, 06:23:30 PM
I had been frustrated with the upper midrange peakiness I was hearing. Flutes, piano and 2nd harmonic overtones of lower barky instruments like baritone, cello, oboe, etc with lots of natural overtones.  I attacked it will all kinds of tests on the midrange driver, but I couldn't find anything wrong at all, except for the sound. It sounded like 2nd harmonic glare around 2-3kHz and it would peak on loud passages. I call it flute stab.  I remember having this problem years ago in here with different speakers.

When the Christmas tree came, I moved the stereo 90 degrees against the side wall. The acoustics are great that way, lower and mid midrange is especially muddy and imaging suffers, it has but much better livability. We can even use the fireplace!

The first night I listened to radio, it sounded good, Ididn't notice the peaks, but the radio is compressed and I wasn't playing loud or listening cricitally. Next night listening to Monk on vinyl I didn't notice any plink and plonk in the upper registers of the piano. I should have been hearing it on Monk if anything. So I start thinking shit, maybe it's my new DAC doing it?

Tonight listening to DAC, I gave the speakers a workout with some of my "big system" tracks. Kalevi Aho Symphonic Dances is loaded with bells and brass, flutes and loudness, modern dissonant harmonies, huge dynamic crescendos with piccolos leading the way. I was surprised to hear the speakers sound much more relaxed and listenable now. So the peaks must have been worse in the other orientation due to the room acoustics. I'm wondering if I am getting slap echo in the space between the walls and the 6" thick ceiling acoustic treatments which have wooden sidewalls. The gap is only about 2-3 feet, but it is very long and goes all around the room. But the wavelength for 2-3 feet is 450-700Hz, too low. I'll have to stick a mic up there and run the sweep, and look for other ways that 3k stuff could form. Maybe it's just too much glass windows, or corner echos?

In a related story...  Yesterday I gave the midrange cones a good fondling. The paper is extremely stiff and the cone is actually a curved wall which prevents bending. There is no give at all in the cone wall. Pressing very hard I was surprised that I couldn't make it bend at all. As the cone goes down into the voice coil, the angle gets much steeper than at the outer edges. This further reduces flex because the steep angle of the cone makes a stronger cone. All this should help reduce cone cry, screaming, breakup distortion, whatever you want to call it. And I couldn't find any evidence of that with measurements. That's good because I want to build some other boxes for these drivers but I was worried a little about the midrange if it was screaming.  Zaph just published his tests of this JA8008 midrange driver on his blog. Passed with flying colors! But those drivers T/S specs look like they aren't broken in yet.
http://www.zaphaudio.com/blog.html
Scroll to December 4, 2012 entry.

I still intend to do some torture test multitone distortion tests on the midrange with ARTA to make sure it is behaving in the upper midrange frequencies. But for now it seems to be mostly gone. But the other acoustic problems of this orientation are a bigger problem, which is why I choose the less feng shui orientation most of the time. Sounds better except for the flutes.

I remember having this problem a few years ago in this room, but it seemed lower in freq. But for some reason it really came back strong with these speakers in that orientation. A sine sweep at the listening position showed nothing. A puzzle.
Title: Re: DTQWT-12
Post by: BobM on December 16, 2011, 05:05:46 AM
Room treatments are God's way of saying he loves us and wants us to be audiophiles.
Title: Re: DTQWT-12
Post by: rollo on December 16, 2011, 07:40:26 AM
  Richadoo did you break the drivers in fully ?

charles
Title: Re: DTQWT-12
Post by: richidoo on December 16, 2011, 07:58:24 AM
Yes, they are on 12 hours a day since I finished them, maybe 5 months ago? They stopped changing after a couple months, but the 1st month they changed a lot. Thanks

I guess I'll need more room treatments! Lucky I have 2 more phases planned.  :twisted:
Title: Re: DTQWT-12
Post by: rollo on December 18, 2011, 09:51:23 AM
  It seems the Calif. DIY crowd led by Nelson Pass are using some six channel amps to drive each driver with one channel.
  Have you ever tried that ? Maybe Shane has a six channel amp to experiment with. The DIY guys really like the results.
  Just thought I'd throuh it out there . Curious myself.



charles
Title: Re: DTQWT-12
Post by: richidoo on December 18, 2011, 10:19:42 AM
Thanks Charles, Yes, I am very interested in that. The benefits of active crossovers and direct amps are too numerous to mention. Direct amplification will be required to do the kind of active crossovers and room correction that I want to do in future speakers. I did active on my last OB speakers, ELips, so I have enough amps. I'm not a fan of the Pass xo solutions, but I have a very nice Rane pro xo and a Behringer and I can make an analog active XO from scratch.

This speaker does not lend itself to active crossover, for reasons described in the designers' concept article. Something to do with the phase of the drivers as their rear waves combine together in the horn. Of course, the simplicity of passive xo with one amp is a major benefit.
Title: Re: DTQWT-12
Post by: Vaaa on May 18, 2012, 07:08:00 AM
My new DTQWT-12-V:
Use 38mm Baltic Birch all over! At max SPL the cabinet is like a rock. 0 vibrations, as it should be for something that weights over 300 lbs each.

External x-over with adjustable tone, and select-able amp input.

Baffle is correctly rounded based on diffraction models.

Supra Silver wire used.
Gold plated connections.

Now I need a room X5 bigger. Buying a house for these monsters!

I have only had the speakers done for a week so NO review on sound just yet, i will give them half a year. But initial impressions: BASS is perfect! So deep, hearing new things in each recording. Mid-range and tweeter are perfectly integrated, lots of break-in to come.

LOGIN to see photos.

(http://www.audionervosa.com/index.php?action=dlattach;topic=3070.0;attach=3664;image)
(http://www.audionervosa.com/index.php?action=dlattach;topic=3070.0;attach=3666;image)
(http://www.audionervosa.com/index.php?action=dlattach;topic=3070.0;attach=3668;image)
Title: Re: DTQWT-12
Post by: richidoo on May 18, 2012, 10:09:07 AM
Looks good Vaaa! Welcome to AN!

Please describe how you stuffed the horns for acoustic damping.
Did you use the Eminence drivers?
Is your "external crossover" active electronic?
Thanks!  
Rich
Title: Re: DTQWT-12
Post by: etcarroll on May 18, 2012, 11:34:17 AM
Vaaa - sweet.

When's the gtg to listen?  8)
Title: Re: DTQWT-12
Post by: Vaaa on May 26, 2012, 09:06:45 AM
I stuffed based on what Troels suggested on the build page, as the speakers break in move i will perform analysis and play around with stuffing.
Any suggestions?

The crossover is not active, uses wax-coils/Superior Z-Cap/Silver-Z-Cap.
external xover lets me play with parts, adjust, balance, ect, and i can try active later as well.

I know I was not going to review sound just yet but Wow.
with each day the sound gets focused, deeper and the speaker seems to disappear.
the horn loading is amazing, drums and large orchestral music sound so natural, never going back to bass reflex crap speakers. and with 2 12s and the large mid the cones don't even move yet it can produce HUGE sound.

Size matters. large speakers make large sound. and need room to breathe.

new amp is in order now. any suggestions.
looking to build:

300b -trans interstage coupling. 8 watts
or
211 --trans interstage coupling. 21 watts -huge cost
or
845 --trans interstage coupling. 21 watts -huge cost
or
class a solid state.????

I dont think 8 watts is gonna be ample for a Mahler symphony.
Title: Re: DTQWT-12
Post by: richidoo on May 26, 2012, 09:44:02 AM
Thanks Vaaa. I experimented with stuffing quite a bit. What sounded best and kept the lowest extension was pushing the fluff to the sides so there was left an open passage through the entire horn length.

I have the same crossover as you.  :thumb:

You definitely need 20W+ to play anything loud complex and clean. SS is nice to have on the bass. Pass XA30.5 would be real nice or 50W+ PP tubes.

Did you use the same exact stuffing materials recommended by Troels and sold by Jantzen in the kit?

Where do you live, Vaaa?
Thanks
Rich
Title: Re: DTQWT-12
Post by: richidoo on May 30, 2012, 05:44:54 PM
Vaaa's posts made me think about my pair of DTQWT. Despite playing for a year in these DTQWT speakers, the woofers were never fully broken in, as seen in the T/S measurements. After the factory recommended torture routine to break them in correctly, now they better match factory specs and should work with the bass horn better. Looking forward to firing them up again.
Title: Re: DTQWT-12
Post by: richidoo on July 01, 2012, 10:35:37 AM
I was able to play the DTQWT-12s at the recent g2G. They sounded better than ever with fully broken in woofers, and especially powered by the Cherry stereo amp, made by Digital Amplifier Company. The speaker requires low impedance amp to control the bass, and also some fullness, both of which the Cherry offers. I am playing them now with Samet i30 intergrated SS PP linear amp, worth 30W. It also sounds very good on these speakers, even better than the 60W version from Samet Audio that I used for the last year.

As of yesterday I had 4 different, full size, full range speakers in the house. It's time to clear house to make room for new projects. I sold one pair yesterday, and these DTQWT-12s are coming up for sale soon.
Rich
Title: Re: DTQWT-12
Post by: Vaaa on July 10, 2012, 06:34:59 AM
SELLING the DTQWT-12???? These speakers can hold their own against $70k+ speakers. I wouldn't do it!!!! they are insane value and quality, all my Audiocrazy friends are in shock by the sound they produce. I wont let go of my pair for decades. Maybe one day I will build a pair of 3x15" woofer per speaker MONSTER speakers but that will be the day I have a gym from a audio room.

I think the D-12's are in the top 3 best speakers next to the Verity Lohengrin II, Sonus Faber Stradivari Homage. They sound better then the Verity in my option with even better bass.

I am very happy I used 38mm wood throughout the speaker. The solid construction is KEY to perfect sound. the front baffle rounding is also very very important. I suggest anyone who builds the 12" version use nothing less or they will greatly compromise the overall sound quality.
Title: Re: DTQWT-12
Post by: richidoo on July 11, 2012, 12:07:52 PM
My wife agrees, she likes the DTQWT. 
Title: Re: DTQWT-12
Post by: Hornologist on July 13, 2012, 04:06:52 AM
Hi Vaaa, your DTQWT-12 look amazing, I am glad to hear that the sound is exceptional. Congratulations Marc
Title: Re: DTQWT-12
Post by: FnAudioDog on July 17, 2012, 06:44:38 PM
Hi Rich,

 Troels has alot of good designs. Unfortunately as with most of us, I don't have deep pockets.The DTQWTs look good. So far they are my top pick. However, I like the way Troels defines the sound of the OBLs as "Sit back and enjoy the concert". The bass is suppose to be like no other. The width of the OBLs is a problem, but something I may be able to deal with. No WAF but id have to keep the volume at 10 instead of 1:00 due to my neighboor's. Damn.

Your thought's are appreciated.
Steve.

   
Title: Re: DTQWT-12
Post by: richidoo on July 17, 2012, 07:41:01 PM
Hi Steve,
The OBL11s do look very promising.
http://www.troelsgravesen.dk/OBL11.htm (http://www.troelsgravesen.dk/OBL11.htm)

They use the same mid and tweet drivers as the DTQWT-12, DTQWT, TQWT, and Quattro. I thought when I bought the drivers from Jantzen that I would build a few of them. But the different crossover parts and different woofers are too expensive to just knock them out for fun. But the big OB does look interesting. The bass might be a little quicker and clearer than the DTQWT12 but it won't play as low or loud. It requires more distance from the wall and takes up more floor space. Probably costs about the same as DTQWT12, one less woofer, but 8 huge caps. Probably easier to build though. The DTQWT12 did take a lot of work to build.

His new Jensen Accu speaker looks really good. Figure $5k to pull that off, and it is a complex construction.
Title: Re: DTQWT-12
Post by: FnAudioDog on July 17, 2012, 10:01:43 PM
Yeah, I think the OBLs won't work for me due to width.
Since I already have an ARC EC22 electronic crossover and two power amps, I'm thinking of building two new cabs for my HiVi-W12 drivers (per side) and building Troels AT-SWs for the top end.
My problem is finding the best software (That I trust) to design the bottom cabs for the (2) HiVi W12s per side.
I currently have Bass Box Pro 6 and WinIsd (freeware) software.
Not sure which one is the better of the two. They will only do closed and ported boxes. I feel like the HiVi-W12s are good bass drivers and just need the right type of cabs.   

Any help would be greatly appreciated.
Thanks,
Steve.

     

Title: Re: DTQWT-12
Post by: richidoo on July 18, 2012, 04:20:01 AM
Sounds like a nice plan. Best to start a new thread about your box. You'll get some good advice.  If you are in small/medium sized room I would go with sealed box, with Qtc of about .6. The reflections will boost the bass to almost flat. You can adjust distance to wall to add more bass. I found it difficult to design ported speakers on my first try, using several different simulators. but you might find it easy as pie. Simulators don't make great ported bass automatically, you have to know how to tune and experiment to get it just right. I intend to try again, but I like sealed bass so much I don't feel the need now. Look for the mfg recommended box design for your woofers, or email them for advice for a clean, audiophile quality ported bass design.
Title: Re: DTQWT-12
Post by: FnAudioDog on July 18, 2012, 02:31:41 PM
Is it hard to sell DIY loudspeakers?
Title: Re: DTQWT-12
Post by: richidoo on July 18, 2012, 04:01:11 PM
Is it hard to sell DIY loudspeakers?

Not with the right price and a well known design. It's harder for a homebrew design, but wise buyers can see value.
Title: Re: DTQWT-12
Post by: gregfisk on August 28, 2012, 03:37:27 PM
Hi Richidoo,

I followed this thread back when you built these speakers and see that you may want to sell them. What part of the U.S. do you live in? I live in the Seattle area and have been interested in building a pair of these or the 10" model. I have a very large room.

Thanks,

Greg
Title: Re: DTQWT-12
Post by: richidoo on August 28, 2012, 06:39:17 PM
Hi Greg, I'm in NC.  I have a very large room too. The speakers sound big and very satisfying.

I would be curious to hear the two designs, the 10" woofer DTQWT and the 12" woofer DTQWT-12, compared side by side. The smaller horns have faster taper and less horn volume so there is more sound difference in the bass besides just extension. The smaller has the benefit of Troels own horn tuning experience. The new kits include the original stuffing materials that Troels used, so you can duplicate his speakers exactly.
Title: Re: DTQWT-12
Post by: WireNut on August 28, 2012, 08:19:55 PM
Hi gregfisk,

 I have been looking at Troels DTQWT-10s and the DTQWT-12s for months now. IMO i think the  DTQWT-10's look better then the 12s. But then again, I don't have to worry about the WIF and also my living space is 12 x 25 which would be good for the  DTQWT-12s.
 The cost of the 12's versus the 10's seems to be minimal. The extra cost of the 12's are the wood, and a very small increase in the cost of the 12 inch drivers. I estimate $200.00- $300.00.
 If I built the DTQWT-10s and had the space with no WIF I think I would always be asking myself "What If ".
But that is DIY.
 I think either way you go the DTQWTs are a good design and something you will be happy with for a long time.
   
I have estimated the cost of the DTQWT-10s at $1635.00 +  the additional cost for cabinets,wire,ext.

The 12's would add approx $200-$300 extra.
Plus all of your time to build them.


 
Title: Re: DTQWT-12
Post by: gregfisk on August 29, 2012, 11:06:00 AM
Hi Richidoo,

Thanks for responding, I guess buying your speakers would be costly because of shipping. Can you tell me how these compare to other types of designs such as ported box, OB or sealed box speakers? I'm also wondering if you have tried them close to the front wall and how they sound there? My room is large but I can only bring my speakers out from the front wall about 2' because I run into the ends of my couches. I was thinking this design would be good because Toel's states they can be placed close to the front wall, the woofers are rear firing and the midrange and tweeter are well above the ends of my couches. I currently have Aerial 7B speakers which are a 3 way rear ported design but I'm really not that happy with them. The metal dome is painful in my lively room and I had to put them on additional stands to get the bass out of them.

Thanks for your input.

Greg
Title: Re: DTQWT-12
Post by: gregfisk on August 29, 2012, 11:10:50 AM
Hi WireNut,

I have been going back and forth as well because of the size of my room. I agree with Richidoo in that the 10" version is a safer bet and like you said it would cost a bit less to build. I don't have any experience with TL designs so I don't know what they sound like compared to other designs. I do know I need a speaker I can place close to the front wall and many designs don't work well there. If you decide to build Troel's speakers keep us posted.

Greg
Title: Re: DTQWT-12
Post by: hometheaterdoc on August 29, 2012, 11:35:38 AM
you could always buy the parts from him and then you just have to deal with the cabinet construction...

if you're not handy with DIY, the freight isn't toooooo outrageous to you... not cheap, but not as bad as I've seen recently... might be worth the few hundreds of dollars....

another option for close wall placement (albeit a commercial one) with high mid/tweets to clear your couches is the von schweikert VR-33/VR-35 design.... obviously more expensive than the DIY option.... but definitely work great in close wall placement in my experience...
Title: Re: DTQWT-12
Post by: richidoo on August 29, 2012, 06:21:14 PM
Yes, they are still for sale. PM me for a shipping quote. Maybe you'll think the shipping price is a bargain compared to the assembly labor. :)  My selling price is just my materials cost.

The speakers are 2 feet deep front to back, plus you'd want some space behind them. I have mine 2 feet from the front wall, in ~11 foot triangle. So the front of the speaker is 4' from the front wall. They could probably be moved even closer to the wall without harm. I have not spent a lot of time positioning them for best bass response. Midrange did sound better closer to the wall (4') than away from the wall (6-7',) but that could just be for my particular room.

The differences between the various speaker types is a big subject. You might get better response by posting that as a new topic in the Speakers section of the forum.

My box opinions: The rear horn type speakers as a group offer a nice, warm, natural bass. The tradeoff for the beautiful warm satisfying sound is transient response. If you like techno-synth dance music, and rib cracking bass impulses, then get sealed subs with 1000W plate amps, not TQWT. Bass reflex is the most popular because it makes loudest LF with smallest box which means highest WAF and lowest cost. Reflex can sound very good, but it often feels like too much bass unless it is on a <8" driver. Sealed is capable of offering the most natural and accurate sound, but is larger than ported and less efficient. OB/dipole eliminates the box sound, and reduces bass modal problems from room reflections. But OB midrange rear echos are distracting to me, like fake soundstage.
Title: Re: DTQWT-12
Post by: richidoo on October 26, 2012, 12:30:04 PM
A little update.

I like the internal horns for extended bass but I also like sealed speakers. So I have designed a new 3-way, all sealed cabinet for these same drivers. I like sealed speakers. I am gathering materials and tools to build the boxes with vacuum bagged foam and wood sandwich. 

I will start a new thread for it.