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
felixx said:
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.
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.
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
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
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.
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.
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..
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..
variac's quote:
"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"
A good possiblility of a group buy, the design based on the Silver Iris spec, with possibility of lower Qts, about 0.7. This way would be cheaper than silver iris?
Just a thought.
"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"
A good possiblility of a group buy, the design based on the Silver Iris spec, with possibility of lower Qts, about 0.7. This way would be cheaper than silver iris?
Just a thought.
Variac said:
dunno-that's thing to ask main RAAL man
I heard them once-in company with now mine RCA babies ;
smallest one RAAL ,in fact prototype of it-as I'm informed ,was connected via 1UF PIO -just as helper tweet;
boy-that was nice amount of air added
talking of OEM and custom:
http://www.goodsoundclub.com/TreeItem.aspx?PostID=3824
I love the idea of a group buy and the concentric tweeter, but why such a large driver? If it's only for the efficiency, that can't reasonably matched in the bass region with dipole anyway.
I'm thinking something like Adire's HE10.1 (anyone try it boxless, my HE8.1's are worlds better as freemen), but with a cast frame, maybe additional Xmax, and I trust you guys to design better performance than that cheap compression tweet. In a 10" or maybe even a 12" and I'll commit to at least half the minimum order.
I've been wanting to put together something like this together with Eminence, but the logistics from here don't make sense.
I'm thinking something like Adire's HE10.1 (anyone try it boxless, my HE8.1's are worlds better as freemen), but with a cast frame, maybe additional Xmax, and I trust you guys to design better performance than that cheap compression tweet. In a 10" or maybe even a 12" and I'll commit to at least half the minimum order.
I've been wanting to put together something like this together with Eminence, but the logistics from here don't make sense.
Variac said:
I can't see getting much more for the money than the SI. Somehow Eminence has coaxed reasonable sound out of the cheap compression driver - surely at the expense of efficiency. That's OK tho, there is a lot of wiggle room there.
Anyway, It seems a reasonable idea (especially since
johninCR will take 50
). Personally I'd like to see a 12" driver, and that it happened sometime this decade - but that's just me being fussy. Most importantly, the buy obviously would have to be run by a trustworthy member with a good ear, good measuring eqpt., and the ability to use and communicate the results of both. Otherwise it's a non starter. Is this worthy of it's own thread? Is there someone qualified that would take it on?
as are the Hammer speakers.
Well, it seems that Silver Iris has done all this for us. They are a little company and I wouldn't want to step on their toes. They might give people here a group buy though. At least their stuff exists and can be tried out. Trusting someone to decide on a driver that no one has heard is pretty risky. I also don't think that the SI is at the level of reproduction that Lynn is proposing. Then again, with some mods, and a better tweeter driver...?
I ALSO remember Eminence saying that they won't "just copy another driver" Obviously if they help someone design a custom driver, they can't just turn around and sell it to someone else.
OTOH, Eminence DOES have a hemp cone guitar driver...Imagine that cone paired with a cast frame and a neodymium magnet.
It could be had with the built in horn for a coax or with a 4" voice coil and no dust cap so our ribbon driver could be attached...
Even a 12" driver might not reach up high enough to work with a ribbon. Shorter ribbons tend to have greater distortion and also burn up, at lower frequencies, unless they are longer than would fit on the pole piece..
( and longer ribbons have limited vertical dispersion if that's important) A 10" might be better- depending on efficiency, and where the lower crossover is to be.
As far as efficiency goes, If the bass is biamped, it can be hooked to a bigger amp, while allowing the coax to handle the mids and highs with a low output amp/. That's why efficiency is still relevent to an open baffle..
Are we OT yet?