Author Topic: DTQWT-12  (Read 127161 times)

Offline tmazz

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Re: DTQWT-12
« Reply #15 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
Remember, it's all about the music........

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Offline richidoo

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Re: DTQWT-12
« Reply #16 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:

Offline richidoo

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Re: DTQWT-12
« Reply #17 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.

 

Offline Carlman

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Re: DTQWT-12
« Reply #18 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..
I really enjoy listening to music.

Offline richidoo

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Re: DTQWT-12
« Reply #19 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.

Offline tmazz

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Re: DTQWT-12
« Reply #20 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)
Remember, it's all about the music........

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• McIntosh MC 275
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• VPI HW-19 Mk IV/SDS/SME IV/Soundsmith Carmen Mk II ES
• Pro-Ject Pre Box S2 DAC/Rasp Pi Roon Endpoint
• DigiBuss/TWL PC&USB/MIT Cables

Offline richidoo

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Re: DTQWT-12
« Reply #21 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.

Offline rollo

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Re: DTQWT-12
« Reply #22 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
« Last Edit: April 30, 2011, 10:44:51 AM by rollo »
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Offline richidoo

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Re: DTQWT-12
« Reply #23 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.

Offline richidoo

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Re: DTQWT-12
« Reply #24 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 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.

Offline richidoo

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Re: DTQWT-12
« Reply #25 on: May 20, 2011, 03:47:00 PM »







Offline stereofool

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Re: DTQWT-12
« Reply #26 on: May 20, 2011, 04:33:12 PM »
Get going...boy  :twisted: :pop!!!
Steve
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Re: DTQWT-12
« Reply #27 on: May 20, 2011, 04:59:00 PM »
Dang Rich, that's a lot of wood  :D

Offline richidoo

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Re: DTQWT-12
« Reply #28 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!

Offline Bunky

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Re: DTQWT-12
« Reply #29 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 .
Remember, information is not knowledge; knowledge is not wisdom; wisdom is not truth; truth is not beauty; beauty is not love; love is not music; music is the best.
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