Great! Thanks for the pix. I've always had a soft spot in my heart for the Westrex gear.
My first post here so I thought I'd share some pics of my Westrex 2226A speakers as they have their roots in Altec technology.
These were a development from the Acoustilens to produce a loudspeaker with a more domestcally acceptable size and characteristics than their predesessors and were apparently developed with assistance from GEC.
The 2080E bass units have an added mass ring, lowering Fs to 32Hz and the photos show the solution arrived at for the mid/hi's which have the designation 2390A.
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Last edited by Andywin; April 25th, 2012 at 02:21 PM.
Great! Thanks for the pix. I've always had a soft spot in my heart for the Westrex gear.
That is one of the coolest WE speakers I have ever seen.
Do you know when they were built and what the mid/tweeter material is? Judging by the baskets/frames, it looks like this may be one of the earliest uses of a non-horn-loaded dome.
Steve Schell: Comments, please.
They are circa 1961/2 and were first announced in 1959 although with 2 tweeters that I understand were GEC units used in the prototype. The mid/hi was developed with GEC using the 2090 as the basis which is basically an Alted 288C. The diaphrapms are the original Westrex ones which I thing are pretty much the same as the Altec ones.
I think GEC pioneered using a compression driver as a dome tweeter with their "presence units".
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The Westrex 2080E bass drivers in my 2326A's have an added mass ring around the circumference of the dust cap.
My understanding of mass rings is that they effectively lower the frequency response.
They certainly seem to go as low as the JBL 4333's I used to have that were reconed to 2235 spec and are certainly more articulate. The reproduction og bass guitar and doublr bass id the most realistic I've ever heard.
Did Altec ever go down the path of adding Mass? If not, I think they missed a trick.
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I think that I want to try the added mass to my bastard 418-8H II A8 clones, (but cheating with a graphic equalizer goes a long way to the bass junkie fix I want) and I have the math linked around here somewhere, just can?t link up with my too busy engineer son to run the math. What is that metal ring, copper wire, gold painted steel coat hanger? This 418 has no cooling venting front or back, I wonder if I need to cut out a quarter sized hole through the aluminum dust cover first, then glue on a 416 paper vented dust cover over that, and then add the wire ring, adjusting the wire gauge to fit the mass needed? Just how accurate does the added mass have to be, calculated weight of glue and actual globbed on are two different things?
"James, a little knowledge is a dangerous thing!" World's scariest Volvo: [url]http://www.youtube.com/watch?v=AKn-LTNa4rc[/url]
Correct, as well as increase Qts, so no 'free lunch'. Only by making heavier diaphragms, VCs AFAIK.Originally Posted by Andywin
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
GM, Please except my ignorance(and spelling), but please explain more in depth the Qts stuff? And you have to type slowly.
"James, a little knowledge is a dangerous thing!" World's scariest Volvo: [url]http://www.youtube.com/watch?v=AKn-LTNa4rc[/url]
It takes a considerable amount of added weight referenced to the driver's moving mass [Mms] to make any major change, so the more accurate the added mass, the closer to hitting a target set of specs. For example:
12" driver/40 Hz Fs/0.4 Qts/60 L Vas has a Mms = ~78.4028 g. Adding this amount reduces Fs/SQRT[2] = 28.28 Hz and Qts increases by SQRT[2] = 0.566, SPLeff. drops by a factor of 4 [~6 dB].
Since the motor will run hotter due to lower efficiency, adding a cooling vent seems a good plan, though if used in a MI app it may not sound 'right' anymore.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
I already 'two finger' type at a snail's pace; any slower and I'll never finish.
Qts is the driver's total quality factor that basically tells us how powerful its motor system is with it more powerful with decreasing Qts and vice versa. For an in-depth tutorial you'll have to either get a book or browse the many on-line ones such as these and if you still need a clarification or two, I'll try to answer them:
The Subwoofer DIY Page - Definitions
mh-audio.nl - TSP
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
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