Beyond the Ariel

[swak]

Fane also have non-coaxial vintage-like alnico guitar-models, the Axiom AXA.10 and AXA.12, and seem to be very nice. The specs. claim usability to 6/5.5kHz and have a 1.75" VC. A BL of 19 /24.2, Qts 0.52/0.65 and a gms of 31/53 gms respectively. Sadly I see no curves.

here is a link of the 15" Fane coaxial I mentioned before http://www.prodance.cz/protokoly/DX15HE.pdf

Here more (lots of) Alnicos at very good pricing (what about modding?): https://taweber.powweb.com/weber/ (at least they show an Alnico driver doesent have to cost so much) I read somewhere they are made by Eminence.

Given that Eminence can build drivers up to specs in small quantities (even a Group-buy would probably do), and that they work with Alnicos, it could be a very nice community project under Olsons lead. (A bit of fantasy: two design teams 1) motor and chassis team 2) cone material/profile + surround and spider team, plus membmer distributors in America and USA....it would be a great project). Even a little (but very little) overprice could be directly distributed among the participants/designers. I would be in for distribution in Europe as my technical abilities don´t allow for much more.

[Russell Dawkins]

Originally posted by Lynn Olson
Another appropriate material is soft felt, which like rubber, improves the mechanical termination where the VC meets the cone. Without some damping at this absolutely critical location, the mechanical disruption caused by the turn in direction and materials with dissimilar speeds-of-sound creates a substantial reflection, which then in turn creates standing waves on the cone.

Does this suggest, then, that a properly designed dust cap will help the sound of most drivers more than a "phase plug"?

[BudP]

Hi Russell,

When I was working with Mille Nestorovic, we discovered that if we used the same 2" polycarbonate dome, that was used on the midrange driver, for the next frequency band and attached it directly to the end of the voice coil, 2" by design, with the voice coil end protruding through the cone center just far enough that the "surround" of the dome was firmly seated in the still moist PVA that coated the entire cone, we had greatly reduced aberrant behavior in upper frequency response areas. Very smooth roll off and a surprising lack of phase induced peaks and valleys. When we applied the EnABL process to just this dome even those remaining shallow hills and dales disappeared. This was an 8 inch driver with edge wound voice coil on a Kapton former, and worked from 20 Hz out to 2 kHz, crossed over to a 10 inch on the bottom with Mille's patented cross over that turned the 10 inch into a passive radiator at about 60 Hz, in a gradual slope.

This EnABLed polycarbonate dome was a very expensive solution and so we continued to experiment. Eventually we found that a smooth, .040 thick coat of RTV caulking, spread on the inside of the felted domes, provided the same performance, once also coated on the outside with the PVA that covered the rest of the cone, as that of the bare polycarbonate dome. The felted dome was attached to the cone surface very close to the voice coil former and the RTV was in intimate contact with the end of the voice coil former, to keep the energy left there from ringing in storage. Really quite a problem getting the tinsel strands and coil wires into that small area smoothly and safely tucked away under the dust cap.

None of this approached the fully enabled driver, with poly carbonate dome, for audible performance or measurement purposes, but the cost factor was perhaps 1/20th in time required to process the post construction treatments. Even so, the performance of the PVA coated cone and dome, with RTV applied, was enough to walk away with best sound in show at numerous European audio shows. Mille especially liked attending one held in France.

We experimented with phase plugs throughout this time. Nothing we used caused us to change from what we were doing. The shapes ranged from spike to mushroom door handle in contour. The phase plugs always created a new problem while solving the one we were after. Just killing all possible can resonance and center pole piece resonance and brutally enforcing a continuous boundary layer across the dome and cone provided extraordinary results sonically and measurement wise. Again not to the level of refinement available with the EnABL process, but Mille was very concerned about legal encumberence if we used that, at the time, unpatented process. He was even more concerned about a legal fray if I did patent it.

Bud

[Graham Maynard]

Hi Bud,

There were drivers manufactured as you describe with the felted centres, but I cannot remember the make. Maybe 1960s.

Cheers ...... Graham.

[chrisb]

Swak , et al;

perhaps a bit OT, but interesting gadget from the Weber site

http://www.webervst.com/blocker.html

Reminiscent of the diffuser dome on the rear of suspended tweeter pod on Stew Hegeman's speaker (latest incarnation via Morrison)

http://www.morrisonaudio.com/morrison_loudspeakers.htm

[ScottG]

Believing your 12" Tone Tubby open baffle as a "base" to be your best bet in achieving what you want..

How about:

High Freq.s:

Two BMS 4540ND's per side.

Radial compound configuration (one driver facing up, the other driver about an inch above facing down to the lower driver).

Nice wood waveguide limiting vertical dispersion (looking like two nice wood round platter bottoms facing each other - the center of a very stubby "hourglass" shape having two shiney 1" compression drivers in the "interior" center).

Crossover in just about any configuration you want, the only real limit being ultimate spl's.

The Tone Tubby would be the limiting factor with respect to linear decay.

Freq. extension to 30 kHz.

Custom autoformer from Dave at intact audio to pad the thing down.

Midbass freq.s:

Supplement open baffle loss.

1 Supravox 285 GMF.

Low mass high eff. driver to complement the character to the Tone Tubby. It has a "natural" freq. response needed to support the Tone Tubby for open baffle loss compensation. (..good linear decay character in this lower midrange as well.)

Use driver with magnet facing forward.

a 1st order electrical ".5" filter for it around 200 Hz. If a parallel crossover you could use a Mundorf Zero Ohm inductor.

Target baffle 13.5 inches in width. Height - dependent on listener's preference. Ear height should match top of baffle.

Tone Tubby pushed all the way to the top and one side of the baffle's edges. The Supravox on the same side at the bottom of the baffle similarly situated. On top of baffle is the radial tweeter assembly.

[Lynn Olson]

Originally posted by swak
Fane also have non-coaxial vintage-like alnico guitar-models, the Axiom AXA.10 and AXA.12, and seem to be very nice. The specs. claim usability to 6/5.5kHz and have a 1.75" VC. A BL of 19 /24.2, Qts 0.52/0.65 and a gms of 31/53 gms respectively. Sadly I see no curves.

here is a link of the 15" Fane coaxial I mentioned before http://www.prodance.cz/protokoly/DX15HE.pdf

Here more (lots of) Alnicos at very good pricing (what about modding?): https://taweber.powweb.com/weber/ (at least they show an Alnico driver doesent have to cost so much) I read somewhere they are made by Eminence.

The Weber 12A125 looks interesting - lots of ribs for progressive decoupling, AlNiCo magnet, and a fun sound clip by The Heard Mentality, too!!!

At the risk of completely disorganizing the Loudspeakers forum, I have foolishly gotten two threads moving in parallel. The other thread, though, is more about horn/dipole integration, and brings ScottG's insights about drivers in the pro world.

[ScottG]

Ha.. 11 ounces.

I'll see your 11 and raise you 24 more for about the same price:

http://www.eminence.com/guitar_speak...2&SUB_CAT_ID=4

Ummm.. Don't look to hard at the upper freq. response though. (..and its likely the same story for the weber.)

[Variac]

I went through pretty much all the electric guitar speakers at Eminence and they all have very peaky (usually a couple of peaks) hi ends. The high end we're talking about is around 2k , not really very high in terms of what we have discussed.. The Cannibus Rex is pretty smoooth until it goes wacky.

http://www.eminence.com/pdf/cannabisrex.pdf

Might make a good "helper" speaker to support the low end of the main driver?

Here is a pretty well behaved curve that then rises 10 db in half an octave!
http://www.eminence.com/pdf/blackpowder.pdf

and here is an "acoustic" guitar speaker with hemp cone:
http://www.eminence.com/pdf/acoustinator-nh2008.pdf

Makes it hard to believe that the Tone Tubby is very flat at the high end also. Which makes one wonder how it can work for hifi without serious eq. Maybe there's things more important than flat response? MAybe the TT actually is flatter? Maybe again, it works as a "helper" driver..

Makes the hifi Hemp Acoustics more intriguing than ever...
Especially if that tweeter on the coax is really a Radian (just a guess but it would help explain the high price...)

[mige0]

Hi,

some interresting facts and opinions about different magnet materials under:

http://www.diyaudio.com/forums/showt...033#post605033
"http://www.diyaudio.com/forums/showthread.php?postid=605033#post605033"

greetings
Michael