"MooseStyle BVR" with Feastrex D5nf driver

[jrebman]

Congrats, Rich!

How thick is your BB?  What are the overall dimensions of the speaker, and what kind of finish do you have on the speaker?  Unfinished BB that's too thin for large unsupported areas can sound a bit weird.

And really, a 5 incher that's beaming?  Something doesn't sound quite right there -- is there a phase plug?

-- Jim

[richidoo]

Thanks guys.  Carl, my tools are your tools. Just sign this liability release form....

Jim, howdy partner! BB is 18mm, aka .69". Speaker is 58" tall, 10" wide, about 14" deep? Going from memory.  I don;t have any finish on there yet, which I am starting to gather is not good. Dave recommends a couple coats of varnish or something to cover it up. I love the look of raw wood, but I think that won't fly this time. I was thinking about painting it with latex paint. That will damp even better than varnish, but it is vinyl though. Does that piss off the Audio Goddess of Purity? I was thinking of painting same color as my fireplace - dark green.. Ahhhhh.... that's niiiice..... 

I did put some extension clamps across the horn mouths, that helped.

It is a 4" driver, with large wizzer and wooden phase plug. This speaker goes right up to 20k, so it should beam that high at 4" wide.  The beam is very high freq. Ducking out of the way is more pleasant for me, leaving the 12-15k stuff where the music is.

So paint it, huh? cool.
Thanks
Rich

[jrebman]

I was thinking more along the lines of a water based lacquer -- or nitrocellulose lacquer (as in musical instrument finish.)

Very time consuming to do right, and the water base is far easier and safer to work with and cleamn up, ammnd either will look beautiful.

If you really like the end result of the cabinet and want to really go crazy, you could build the sides out of glued-up edge grain BB -- the laminations of the ply run perpendicular to the flat surface, instead of parallel to it.  Truly masochistic, bbut ultra rigid.

I'm going to try this on a simple BR box for my F120As this summer -- time permitting.

P.S. -- I sent my EnABLed F120As to Planet 10 so they could design an optimized fonken cabinet for them.  Like the Maiko, there are a few people who may want to build these, so I volumnteered my drivers to help the effort a bit.

Well, maybe Mike will get his Maiko started fairly soon, then I'll get to hear them.  I might suggest two layers of 9 mm BB with a constrained layer of green glue between them for the main pieces -- sides, back, etc.

Wish I could come to the G2G, but foot surgery is going to be happening soon.

-- Jim

[richidoo]

That sounds pretty cool Jim. I never tried water based dope, but sounds interesting. Like you said, it will require many coats to build up any mass, as dope is originally intended to be very lightweight for airplane skin. It dries glossy and has a musical sound because it is actually dissolved wood.

I am getting the impression from various damping experiments that I am doing on the birch cabinets that the BB sound is rather stubborn to dilute. So I'm not sure low mass dope will have much influence, but I never know till I try it. I think 4 coats of duct mastic might be more like it to eliminate the birch sound. Yesterday I tried this, it helped a lot but still sounds like birch and is too heavy. It is slabs of treated 2x lumber screwed to the speaker sides with 100 screws per speaker, ever 4-6 inches. The speaker is less confused sounding and images 100% better, but is now way too dark. And still sounds like birch.

There was a cool interview with Magico designer in TAS magazine a couple months ago about wood resonance in speaker cabs. He uses 1" BB on edge like you describe in the Magico Mini and the new V3. I like that idea, but you're right it is tedious, and maybe partly why they cost 30 big ones.

I have some more bracing, tensioning and stuffing to do before I pretend to know the final sound. But I will put wood finishing on the list too. I like the sound of raw spruce, but not BB.
Thanks
Rich

[miklorsmith]

Man, those are cool Rich.  They're bigger than my Defs with six 10"ers each!   

That kind of woodworking is very impressive to me.  When I built my TNT boxes, aside from the sloped front baffle, it was about as simple as it gets.  Still, it was a major effort and came out looking like crap.  Kudos.

I bet those sing beautifully.  I look forward to reading about the impressions when you have your G2G.

[richidoo]

Thanks Mike. It took a little while to build them. Here are some shots of the interior plumbing, it is rather ornate, designed to minimize resonance in the middle box so it won't get amplified in the horns. Notice the driver mounting, it is held in place with a thread rod coming in from the rear. This locks the rear of the driver motor hard against the internal bracing and lets the driver bezel float free of the front baffle, except for a soft rubber or cork gasket. But it all has to be fit and tweaked. It is like a 911 GT2 race car, it rolls out of Porsche factory finished, but not even close to ready to race yet.

[richidoo]

More to report...

The designer Dave Dlugos from Planet10 added bracing to cure the resonance we got on the first try. A couple panels went into each horn, and some external slats on the outsides of each horn, perpendicular to the internal braces.  A spine of bracing was also applied to the rear panels.

Altogether the speaker is greatly improved. There is still some boxyness and woodyness, and tapping the wood still has a little resonance, but it is listenable now, at least for me. I have a high tolerance for audio pain when the rest of the presentation is this good.

I plan to add stuffing to the inner chamber tonight which should further improve things by damping down the middle and upper frequencies and prevent them from being amplified by the horn. I will also paint them with a couple thick latex coats to damp the wood a little more. But of course I had to listen first, so I could learn what stuffing does - besides I just couldn't wait any longer. It feels good to check this project  off the 'to do' list. It has been a long time coming.

But I do intend to build it all over again a couple more times using different materials which should require significantly less resonance control, and so they should build much faster. I have high hopes for those. The baltic birch is just not my cup of tea dispite its long history as material of choice for single driver designs.

These things have incredible tone, dynamics, clarity, detail beyond your wildest imagination. Imaging is surreal. I can't listen with my eyes closed, the imaging is too distracting. I keep feeling there is someone really there and my subconscious reflex opens my eyes to see. With further improvement in the resonance and type of wood I think it will be something very special. The drivers are the star of course, they really deserve the finest cabinet possible, and reward richly for the effort.

So yes, if you come over on May 17th you will be able to hear them this time. Maybe even further revisions...
 

[miklorsmith]

Wow, that's killer Rich.  You should sell those cabs, I'm sure somebody would pay for them.  Have you tried any BlackHole 5 or dynamat or modeling clay or similar materials to tame the resonance?  They'd all be most at home inside the box of course.  The modeling clay especially could be fun because it's non-permanent, stays soft forever, and can be moved and tweaked in no time flat.

Nice work Rich, I'd really like to hear those.  The widebander thing is right up my alley.

[richidoo]

Thanks Mike!  I listened again tonight (2nd impresion) and it is not as bad as I may have let on first post. It's easy to listen through the remaining wood, but it would be nice to clear it out altogether. Or if wood must remain, make it pine or something that sounds good naturally.

I have not tried any of that stuff, but about every 4 months Carl is recommending I try black hole for something or other. John uses plasticlay in TTs, but I never thought about it in a speaker box. Good idea! This speaker's designer, Dave Dlugos believes that damping birch only makes the resonance lower in frequency which sounds worse. He tends to lean toward tensioning and bracing it to raise the resonant frequencies out of the passband. I like the idea, but in practice it is more difficult to build, but the results seem to be worth it. I am really enjoying this speaker.

I hope what is happening is the midrange freqs inside the speaker are being woodied up inside the box and more in the horn while amplified in the horn. Some wool inside will damp mids coming out of the tuned port, and might solve it.

I'd like you to hear them too!!!! I am considering making them, but I don't know where in the hell I would find the time. Lots more development to do before they could wear my brand name, but potential is there.

My wife dug the look. She said they looked cool, but strange. I think they are right out of the Millenium Falcon's dedicated 2ch cabin. Painted silver with red leather padding on the sides between the slats... And big 2 inch thick power couplings going in both sides, and  few blinking lights and screens on the front. haha... 

[jrebman]

Rich, Very cool.  Another suggestion -- laminate, with green glue or not, something completely different with altogether different resonant characteristics from wood.  Phenolic -- the high grade linen composition type might be a good choice.  Well, this is about experimentation, isn't it?   At least it's a lot easier than the edge glued plywood .

Looks like my "Uber Fonken" F120A Fonkens are not too far off., so it will be interesting to see how these compare to the Feastrex drivers when Mike finishes his cabinets (miklorsmith, different Mike.)

The progress sounds good and promising.

-- Jim

[richidoo]

I like the constrained layer idea. It is from the damping school. I have to do that on another speaker than this, too much effort to make it tensioned. If I damp it is the opposite direction. Either way damped or tensed, the resonance is forced out of band where the wood will vibrate.  Damped requires mass, which makes a speaker heavy. Legacy's will be the last heavy speakers I ever own. 

Your F120As are getting the super dot treatment right? What's it called again? You guys can have your own horn fest out there pretty soon!! Mike is getting itchy to build the Maikos too. He is just waiting for me and Phil Townsend to make all the dumb mistakes first.

I think I will try the edge glued scenario next, but with a twist..  I would like to find a source of phenolic like WIlson uses.
Thanks
Rich

[jrebman]

Rich,

The F120As have already been EnABLed by Bud -- who had nothing but good things to say about them; very good things.  I then sent the drivers to Planet 10 so they could use them to develop and tweak the Fonken for the F120A.  Beyond that, the drivers will be left stock for now.  Dave tells me that the design is done and wood will be cut shortly.

Didn't know wilson used phenolic, but makes sense -- the stuff, especially the super fine grades are super dense and heavy, and it's not cheap either.

I'm confident you will come up with something great though, whatever it ends up being.  Then I may have an amp to send you.

-- Jim

[mgalusha]

I think I will try the edge glued scenario next, but with a twist..  I would like to find a source of phenolic like WIlson uses.

Rich,
Very cool, I'd love to hear these.

US Plastics has several varieties of Phenolic sheet in various thicknesses of 24 x 48 inches and 48x48.

http://www.usplastic.com/catalog/category.asp?catalog%5Fname=usplastic&category%5Fname=79&Page=1

[richidoo]

Thanks Mike, I get their catalog twice a year but never thought to look there!!

I stuffed them with LOTS of poly wool yesterday, about 10oz each. Too much. It helped the midrange woodyness a lot, but killed the magic and detail. I took out most of it leaving only 3oz per speaker, much better, but still some stuffyness for the wool and still a trace of woodyness, so a compromise is gonna be needed. Big surprise! haha

I spoke to a friend in MA who just recieved his new Feastrex 9" drivers, about to start building his cabinets. I can't wait to hear those.

[richidoo]

Maybe you guys can help me understand this. Why does a horn have a horny coloration?? It is the geometry of the horn, or is it the resonance of the material the horn is made from. The horn should just be an amplifier, right? If the material it was made from was totally nonresonant, would the horn give a coloration? Trying to decide if rebuild with new material or redesign with rounded shapes.

Maybe squared off DIY type horns are more prone to the empty box sound than structurally stronger and rounded spherical horn?

Has anyone ever heard avante garde, with ABS spherical horns? Are they noticably colored? I assume that they will sound different as you move in and out of the center.
Thanks
Rich