High Efficiency Speaker Asylum: Re: Waveguide geometries by tomservo Need speakers that can rock with just one watt? You found da place.

For Sale Ads FAQ / News / Events

Posted by tomservo (M ) on January 9, 2005 at 16:13:40

In Reply to: Waveguide geometries posted by Pooge on January 9, 2005 at 06:52:28:

Hi

"Tom, I recall reading somewhere that you used a radius from the throat into the cone. If this is true, how does it affect your situation regarding the Peavey patent to Hughes, i.e., 6059069?"

I used a radius transition at the throat from the very first Unity product, one my old boss called a VFL after hearing it.
AS this was several years before the this patent was applied for, I don’t think we would be infringing by continuing to use it.
Of course back then when I writing the text parts for the Unity patent, I also didn’t think a radius here was patent able and never considered mentioning it. To be clear however, I have been wrong more than once on what lawyers and money can accomplish.

snip
"The shape gently curves outwardly until it reaches conical assymptotes. Earl has stated that it is the gentlest curve to do this, thus reducing diffraction in the waveguide. Also, the apex of the cone is still visible along any wall of the waveguide."

I would presume that his "shape" is exactly that an optimum geometry, I have not played with or heard any of his OS horns (in home listening) and have not slugged through the math with examples to get a feel for what it says however.

"Tom, you mentioned B&C and BMS drivers. I haven't looked at the BMS ones, but the Radian 475 and Beyma CP380M for their extended response and use of other than a titanium diaphragm (I am one of those who prefer the aluminum 2441 diaphragm to the titanium one). I believe I read you had some experience with the Radian. Although it looks the most interesting to me, and the fact that it can be equalized down below the power response knee to mate with other drivers, I don't know about its distortion characteristics or other considerations. Also, you can't get specs for the phase plug flares. Do any of the drivers you or I mentioned (or not mentioned) behave better than the others in the phase plug for this application?"

I used the 475 in our first product, the VFL, of the drivers I had tested back then, it had the best (extended) HF response. Unfortunately they proved to be fragile in the night Club torture they were used in and I eventually switched to a B&C.
It had a little less at the very top but right off the bat the failure problem ended, essentially no failures. The 475 Simply died anywhere near its rated power where the B&C was (comparatively, and I use this word carefully) "Bullet proof".
I also use a couple BMS drivers, they (like B&C) make some very good drivers at a good price.
Last summer I rebuilt a pair of Altec A-7’s for a friend, I replaced the Altec Driver with a BMS 4550 and not only was it more sensitive, had flatter response but it went out an entire octave higher "flat".
I used a JBL 2226 for the low range (normally I shun expensive drivers except he had them and it seemed appropriate to have at least something "Lansing" in it) and re-tuned the box and the end product had a 2+ octave wider bandwidth than the original with several hundreds of degrees less phase shift through crossover. to boot.
I took pictures and intend eventually to do a DIY article because when they were done the they sounded wonderful.

So far as the home, a Radian might be just fine, I have also heard that there replacement domes for other brands are very good, even better than the original at times.
Distortion wise, low frequencies are a big problem. The antidote is headroom, this means you might want to look at the 1.4" exit inch drivers, they have the radiator /motor of a 2 inch but a somewhat smaller opening, allowing use in a wider angle horn.
You might want to look at the BMS coax driver too speaking of headroom although I am not sold on the crossover they have.
Phase plugs, I am not up to date on one design vs another although I do think about driver design from time to time, just not in a position to do anything about it at the moment..
Cheers,

Tom Danley

This post is made possible by the generous support of people like you and our sponsors:

Sonic Craft

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---