Acoustat reconfiguration

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Hello speaker gurus!

I own a pair of Acoustat model II speakers that I purchased new around 1980. They are the ones with two standard Acoustat electrostatic panels mounted side by side in each speaker, that were superseded by the model 1 + 1s around 1982. Has anyone reconfigured the model II type to the 1 + 1 configuration, and can anybody tell me what changes one could expect to the sound if I did this?

How about other configurations or different panel angles (I believe that they are at about 7 degrees to each other now.) In some listening rooms there isn't enough clearance to stack both panels vertically. :rolleyes:

I have always wondered what you would happen if you positioned one panel in front of the other and built an enclosure around the space between them. Would this mess up the sound? Could the bass be improved this way or would the enclosure resonances or panel interactions be a problem? Or could each panel be mounted in it's own baffle or cabinet with good results, in spite of eliminating the dipole nature of the the speaker? How would you determine cabinet sizes? Or am I best off just leaving the speakers the way they are and bracing up the frame a bit?

Thank you for any advice you can offer!

Take care,
Doug
 
frugal-phile™
Joined 2001
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I did that...

An externally hosted image should be here but it was not working when we last tested it.


the lower bass leans out -- if i were doing it again, i'd add some wings to the baffle to keep the width about the same...

I also gave consideration to using a pr in a bipole, but with that thin diaphram it isn't going to keep anything in the box...

dave
 
I wish I could....they have been crated since my move from Florida in 1995....FL, CO, DE, CA, PA, CA, NY, NM.....I am not sure the crates will take another move...which will hopefully happen if I can find work...


I don't remember what they sound like and my apartment here in NM is way too cramped to get them out and working...same for the MG-III's...

I am curious if this would help them or just cause problems....do you have any pictures of you mod's? Was the result what you intended? What are you driving them with?


Oh well...back to the PAS-3x and FM-3 mods.

rt
 
I am curious if this would help them or just cause problems....do you have any pictures of you mod's? Was the result what you intended? What are you driving them with?

I posted a picture of the mods a few months ago (maybe a year). Since I'm on a VERY slow dial-up, I'm procrastinating about searching, but when I'm at the computer with the photo on it later today. I'll repost it. The result was exactly what I intended, a bit more bass extension, a bit more SPL capability in the mid-bass, and a marked reduction in the infamous Acustat credit-card coloration. As to drive, the Acoustats have been a test bed for a DD amp design (temporarily stalled due to lack of money, I wish my kid could give up eating); for general listening, I'm using my Small Triode Amp (SYclotron input stage, super-6BG6 outputs, Curcio regulator for the B+, Eico iron), but I'll stick in an Adcom 555 or a Bryston 2B when I need to kick a few more dBs of SPL.

BTW, the panels look remarkably like p10's....
 
The kindest thing to do for Acoustats is use a sub. Even doubling the radiating area doesn't create adequate bottom end. They make really good midwoofers though ...... ;)

BGStatSS.jpg
 
Planet10:

Do you have any more info and details on the work you did? I found no mention of it on your web site.

What changes did you find with the imaging and soundstage, was it more precise or not much different? I definitely don't want the bass to become thinner, but I am wondering about other improvements, whether it would be worth it.

I see that you are using some bass/subwoofer units with yours as well. What are everyone's recommendations for a DIY type subwoofer that will work well with the Acoustats and merge reasonably seamlessly? Should I be looking at a large (15") woofer in a sealed box, or a combination of smaller drivers, vented enclosure, etc?

Sy:

I would like to see your "wings", any tips on search terms to find that thread?

Thank you for all of your helpful replies!

Take care,
Doug
 
frugal-phile™
Joined 2001
Paid Member
The Peasant said:
What changes did you find with the imaging and soundstage... I see that you are using some bass/subwoofer units with yours as well

Imaging got better, soundspace larger. i used the woofers (XO @ 125 Hz) ever before i converted... they allow the removal of the felt strips on the back (there to limit panel excursion ans midrange/top end clarity).

You need woofers that go way up... my enclosures were aperiodic (i just tweaked the boxes they came in) and maybe got to 35 Hz, but were good to maybe 2-3k.

dave
 
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