Richard
We run some parallel paths:
In the 80's I ran Quad 63's (100uf film coupling to remove the LF from them) with your double chambered bass cabinet with Dynaudio's 24W100s . Did an craftsmans corner article in Audio Amateur on them.
I now run ML CLX 's ( big ESLs) With JL Audio 2 x 12 subs on each side.
Run Dynaudio's for 7.1 system with all Relcap crossovers.
In our shop at work we run:
4 x 2245 - 18 inch JBL - 38 to 250 HZ
JBL 2202 - 12 inch - 250 to 1200 Hz
jBL 2441 w 2395 lens - 1200 to 7 kHz
JBL 2405 slot tweeter - 7khz up
All old school JBL with low order RelCap cross overs, except tweeter is 18db octave - ten watts Class A does us just fine
We run some parallel paths:
In the 80's I ran Quad 63's (100uf film coupling to remove the LF from them) with your double chambered bass cabinet with Dynaudio's 24W100s . Did an craftsmans corner article in Audio Amateur on them.
I now run ML CLX 's ( big ESLs) With JL Audio 2 x 12 subs on each side.
Run Dynaudio's for 7.1 system with all Relcap crossovers.
In our shop at work we run:
4 x 2245 - 18 inch JBL - 38 to 250 HZ
JBL 2202 - 12 inch - 250 to 1200 Hz
jBL 2441 w 2395 lens - 1200 to 7 kHz
JBL 2405 slot tweeter - 7khz up
All old school JBL with low order RelCap cross overs, except tweeter is 18db octave - ten watts Class A does us just fine
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Richard, i cross my home speaker at ~ 1500 Hz. And, as i said, The big system i used in my last studio at 700.
Passive crossovers, 24dB/oct (acoustic slope).
No tweeter, response curve of the JBL driver passively corrected. Just a big bass complement to go down to 20Hz that i don't use often.
Believe-me or not: no problem. Very analytic, natural, and you cannot feel any break around the crossing frequency, neither a change in character.
But, as i said, the directivity curves at the crossing frequency is very similar on the two ways (same emissive surface, thanks to horns ;-)
I believe that make all the difference.
At the end, i think i don't like anything crossing after the sensibility peak of the ears (3500Hz). Was never able to add a super tweeter to my system with success. Despite it cut around 16KHz.
Passive crossovers, 24dB/oct (acoustic slope).
No tweeter, response curve of the JBL driver passively corrected. Just a big bass complement to go down to 20Hz that i don't use often.
Believe-me or not: no problem. Very analytic, natural, and you cannot feel any break around the crossing frequency, neither a change in character.
But, as i said, the directivity curves at the crossing frequency is very similar on the two ways (same emissive surface, thanks to horns ;-)
I believe that make all the difference.
At the end, i think i don't like anything crossing after the sensibility peak of the ears (3500Hz). Was never able to add a super tweeter to my system with success. Despite it cut around 16KHz.
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I had 3-way all JBL horn (including bass)system..... it was wonderful. But, I would not cross over today at mid-range. HOWEVER, a large format comp driver like the newer 4 inch JBL 2450J can be used to 500Hz with 100 Watts. That would be better IMO. I should try it again with those drivers.
THx-RNMarsh
That compact double-chamber cabinet started a fire storm of new designs using two chambers and Bose got several patents from their variations. I also had Quads for the midrange only and two transmission line bass cabinets with 30 inch drivers in each. The highs were augmented with RTR electrostatic tweeter panels directly driven from the plates of Push-Pull tube amp (cap coupled). It was my second attempt at SOTA years after the all horn system.
Great memories. Forgot about that double-bass bass cabinet design.
THx-RNMarsh
yes, I blew up the driver trying. What I had to listen to was a 3 way crossed over in the midrange. As wonderful as it was for the time, the newer 4 inch would be better because I could now XO at 500hz.
One thing which helped make it sound so good was I designed/build an electronic XO with continuouly variable slope and freq. Together with sitting the mid/hi drivers on top of the bass enclosure, I would physically move the drivers back and forth and vary XO slope et al until I was able to reproduce a square wave. !!
Crazy all these years!
THx -RNMarsh
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For me the amusing thing is that I haven't gone within 100 miles of the sort of things being discussed now, but it hasn't made the slightest difference in terms of getting quality sound - I use "crap" drivers running full bore for hours on end, with zero fatigue and much pleasure, with any sort of music, from ambient to maximum energy pop. And then I go to some place where one of these "brilliantly" engineered speakers are running - and I cop a face full of bellowing and shrieking - after 5 minutes I would be pulling out a screwdriver and thinking which cone is going to be "heavily modified" in the next second ... 
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Ahhh memories, i too had RTR panels with a home made tube amp, also Jaanzen had the same panel in white which was easier to get as a "service part" back then.
When these were out of commission i switched over to making a good number of generally short lived electrostatic speakers
Richard,
There have always been large format compression drivers that could get as low as 300hz on the right sized horn, only problem was they sounded terrible in that range. Every old PA system had those old Altec 1.4" drivers or 2" JBL's and everybody got as far away from that as they could once other midrange devices were built with cone drivers. You could do that for a long time now, I just wouldn't ever expect the inherent problems to ever change, Forget about ever getting the dispersion pattern to do anything but collapse as the frequency rises with those large throat drivers.
There have always been large format compression drivers that could get as low as 300hz on the right sized horn, only problem was they sounded terrible in that range. Every old PA system had those old Altec 1.4" drivers or 2" JBL's and everybody got as far away from that as they could once other midrange devices were built with cone drivers. You could do that for a long time now, I just wouldn't ever expect the inherent problems to ever change, Forget about ever getting the dispersion pattern to do anything but collapse as the frequency rises with those large throat drivers.
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Is it possible the whizzer on these Betsy FRs resonates at 10KHz? And a way I could fix that?
Wild Burro Audio Labs - Fullrange Speakers - The Betsy & Betsy-K Drivers
I had the thought of gluing strings with some tension from the edge of the whizzer to the cone directly below, but that's probably a terrible idea.
Wild Burro Audio Labs - Fullrange Speakers - The Betsy & Betsy-K Drivers
I had the thought of gluing strings with some tension from the edge of the whizzer to the cone directly below, but that's probably a terrible idea.
A simple technique I use in Audacity is to fade in and out a sine wave, relatively slowly - over 10 seconds or so, at a suspect frequency, and put it on repeat. Play with the volume control and it becomes trivially easy to hear at what intensity of sound the driver, or associated electronics starts playing up.
Keantoken,
The problem with all whizzer cone is that the edge is not terminated and all waves traveling up the whizzer reach the end and revert back down the cone to the center attachment point. If you could put some kind of damper on the exposed edge that could perhaps do something but the added mass would also add mass to that cone section. I just don't see any real solution to that problem.
The problem with all whizzer cone is that the edge is not terminated and all waves traveling up the whizzer reach the end and revert back down the cone to the center attachment point. If you could put some kind of damper on the exposed edge that could perhaps do something but the added mass would also add mass to that cone section. I just don't see any real solution to that problem.
Just came across this, https://www.youtube.com/watch?v=nvzj9CD6Wtw - gives a good idea of what I'm always aiming at ...
And another one, https://www.youtube.com/watch?v=-REW8xCQc5o ... with a cute gimmick - sing along with yourself ...
I like Wrinkle's idea. Making short cuts into the edge and splaying the resulting fingers would triple the perimeter length of the whizzer, perhaps adding enough air resistance to do something useful?
As John just mentioned the whizzer is just such and old idea that never had any real success or solution to the problems it presents. I don't understand myself how we have come full circle back to this terrible idea? I really think you would be better off removing any whizzer and putting a metal dome in its place such as a normal dome tweeter would use attached at the top of the former. Not saying that is a great idea but definitely better than a whizzer.
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