Beyond the Ariel

[DougL]

iii) Perforating the surface close to the edge with an array of holes, such that the holes are smaller than the shortest wavelength (1/4" or smaller), having the greatest density of holes closest to the edge, and the lowest density of holes farther away from the edge.

I have an OB test baffle / test System I can try things on.

Does anyone have a recommendation on a hole pattern to implement this? I was thinking of treating the outer inch with 4 rows of holes with the outer row having holes on 1/2" centers.

Rather than a round-over, would some felt (or other material) Half-round be more appropriate as edge treatment?

Also, how should I treat the Floor transition? Holes, felt or some combination?

Doug

[Sheldon]

Originally posted by planet10


The tech will continue to improve, but the real break thru will be when they figure out how to harness photosynthesis to directly split water.

dave

That would indeed be a breakthrough.

Sheldon

[Lynn Olson]

Originally posted by felixx
Another coaxial option ...maybe....
http://www.paacoustic.com/Product_De...uctID=BM-12CXA

and
http://www.paacoustic.com/Product_De...ctID=BM-12CX38

The BM12CX38 have 90 degree dispersion pattern and 2 inch compression driver.
The BM12CXA look good on paper.

And this:
http://www.paudiospeakers.com/paudio.html
On the first foto in this adress the BM12CX38 look really impressive.

Thanks felixx, the PA Acoustic and Radian line of coax drivers look quite interesting. Even though Tannoy won't sell to OEMs and DIY'ers any more, there are professional products that look pretty well designed - at least the specs are promising.

Still interested in applying the Mamboni, EnABL, and LC-1A treatments to the cones of 12 and 15-inch coax drivers. It might be worth my while to contact these vendors and pay them to apply the treatments and make before-and-after measurements. The reason I mention this is that pro vendors are quite used to re-coning drivers for a reasonable charge - in this case, they'd pull a driver out of production, measure it once as a baseline, apply the mod, measure again, tear off the cone and re-cone it with a new one, measure again, and so on.

Cheaper to have them do all this re-coning at the factory rather than have me make the mods, measure, and then ship it back to the factory for re-coning. I would consider a cost of a few hundred dollars money well spent if I was able to create a new coax driver in the process - and I doubt the pro vendor would mind offering a new product in their line-up. (Mamboni and LC-1A cone treatments are in the public domain, and EnABL is available under license from BudP.)

These babies are efficient enough that the loss of a dB or so to cone treatments would be acceptable - certainly not the case with audiophile drivers, where you're already in the cellar at 87 ~ 90 dB/metre, and cone treatments drop you into the really low 85 dB dB/metre range, way too low for what I want.

[johninCR]

There's a P-Audio distributor here in CR, and I've held these drivers in my hands. They feel like they are built for the military as tank parts, and must be designed specifically for permanent PA installations. You definitely don't want to pay shipping more than one way for them, so that cone mod approach is a great idea.

[BudP]

Lynn,

Send me your cones. I will treat them and you can forward them on to the mfg you have chosen, I have done this before and all I require is a non compete agreement with the manufacturer, so they wont just go into production without at least talking to me. I do have a basic treatment regimine that addresses 99% of all of the drivers I have processed over the years. I only diverge from this scheme for the really odd ball devices, so I do not need working drivers. I would prefer that the outer suspension be attached already though.

Bud

[Variac]

There was a comment in the Hemp Acoustics thread that their coax's look like Radian coaxials. I have to say that they do look VERY similar.

This is a good thing, Radian has a good rep, and hearsay is that their HF drivers are especially good. I haven't ever heard them.

Eminence is very open to making custom drivers and helping "design" them. If I remember correctly, if you order 100 drivers they will design it to your specs at no cost. I think that means mixing and matching their existing parts, but they have a lot of parts! I'm sure that they would be a reasonable place to have do experiments. If it works out, their prices are really reasonable for what you get. The Bastani drivers are made by Eminence, as are the 15" drivers in Basszillas.

[planet10]

Originally posted by Variac
Eminence is very open to making custom drivers and helping "design" them. If I remember correctly, if you order 100 drivers they will design it to your specs at no cost. I think that means mixing and matching their existing parts, but they have a lot of parts! I'm sure that they would be a reasonable place to have do experiments. If it works out, their prices are really reasonable for what you get. The Bastani drivers are made by Eminence, as are the 15" drivers in Basszillas.

As are the Silver Iris.

dave

[Variac]

These ribbons have a good rep as being a step up from the Aurum Cantus , which means they must be pretty good!

theLCY 110 and 130 models:

http://www.e-speakers.com/products/lcy-components.html

http://www.lcy.com.hk/

They also have more equal dispersion to the side and vertically.
If the mounting flange and if needed, the little bump on the back (which is probably a transformer and could be relocated) were removed , they could be used to make a coaxial driver.

Get a 12" pro driver with a 4" voice coil, remove the dustcap, and attach the ribbon tweeter to the polepiece. The tweeter could be placed in a damped piece of PVC pipe first to make a smooth "Phase Plug". If the phase plug didn't flair, it would have a lot less problems with resonances that a horn mounted in front of the woofer cone.

The tweeter isn't quite as efficient as you desire and doesn't go too low, which is why I mentioned a 12" instead of a 15" woofer, but it might have some advantages..

[agent.5]

Maybe we can start a group buy thread. So, your email can saying something like seeking quotes for samples (quantity:2) and for production (quantity:100).

[Zen Mod]

http://www.raalribbon.com/