Acoustat Update

[E-Stat]

Last month, I had found a somewhat rough looking, but otherwise fine sounding pair of Acoustat 1+1s. Yesterday, I begin the renovation project by removing the grill socks. Imagine an eight foot long tube sock that is open at both ends. They need a thorough vacuuming and hair dryer based heat treatment. Here they are naked:

http://home.cablelynx.com/~rhw/audio/sockless.jpghttp://home.cablelynx.com/~rhw/audio/panel.jpg

I was a bit concerned about the condition of the four identical panels because the owner had cats and it was evident from the condition of the grill cloth they had done their own imitation of King Kong climbing the Chrysler Building. Fortunately, there were no tears in the diaphragms. Here's a section of the cloth showing the extreme pilling.

http://home.cablelynx.com/~rhw/audio/cloth.jpg

The next step is to do what I had done years ago with a similar pair of Acoustat 2+2s: make news ones from tightly stretched spandex as is used by the Sound Lab factory. They are far more transparent both to the eye and ear. You can clearly make out the four panel per speaker construction. Up close, you can easily see the stator wires and panel. That translates to a more open and less treble restricted sound.

http://home.cablelynx.com/~rhw/audio/system0306.jpg



After that, I'll update the capacitors used in the power supply and bypass the audio fuse and replace the variable HF control with a fixed resistor. I might add a small value cap at the power supply input for RF suppression.

http://home.cablelynx.com/~rhw/audio/mk121-1.jpg

[Feanor]

Looking good! I love hear those Acoustats in my listening room.

Sad in a way, less than a year before I bought my Magneplanar MG 1.6's, I could have bought a pair of used Acoustats or a pair of used all-ribbon Apogees. They were both smaller models. I was less savvy than today, so I missed my chance. Also I was relatively broke at the time and they were both sold before I was ready to buy.

The Apogees might have be 'Stages'; the Acoustat model I couldn't guess.

[E-Stat]

Looking good! I love hear those Acoustats in my listening room.
I had the luxuries of time and patience in my favor and have been looking for a while. The owner initially turned down my offer. I also considered MG-IIs (an early predecessor to the 1.6) as well having owned a pair just before getting my first Acoustat.

Keep your eye out for either brand. Maybe Flo could help with the Apogees. What I like about the Acoustats is the panels are nearly indestructable and so many exist.

[MrAcoustat]

[QUOTE=E-Stat;386114]I had the luxuries of time and patience in my favor and have been looking for a while. The owner initially turned down my offer. I also considered MG-IIs (an early predecessor to the 1.6) as well having owned a pair just before getting my first Acoustat.

Keep your eye out for either brand. Maybe Flo could help with the Apogees. What I like about the Acoustats is the panels are nearly indestructable and so many exist.[/QUOTE


QUOTE: . What I like about the Acoustats is the panels are nearly indestructable and so many exist.

How very true this is, i have been with Acoustat since 1984 i have owned Spectra 22s - Spectra 33s - 2+2s - and i now own my third pair of very special modified 1+1s and NEVER had a single problem and when the panels get dirty all they need is a good bath and their back to new again.

http://i814.photobucket.com/albums/zz61/MrAcoustat/AcoustatPanelsBathing.jpg

http://i814.photobucket.com/albums/zz61/MrAcoustat/AcoustatPanel.jpg

[E-Stat]

...and when the panels get dirty all they need is a good bath and their back to new again.
While I never did that with any of my Acoustat panels, that's exactly what Jim Strickland mentioned you could do with them when I met him in 1976 when he brought a pair of the model X for review by TAS.

What he actually said was something like "you could hose them down" so long as they were discharged. :)

[JoeE SP9]

This washing thing is news to me. Would either of you be so kind as to elaborate? I'm getting ready to replace the covers on my Spectra's and a good panel cleaning wouldn't be out of place.

[E-Stat]

This washing thing is news to me. Would either of you be so kind as to elaborate? I'm getting ready to replace the covers on my Spectra's and a good panel cleaning wouldn't be out of place.
I'll defer to Andre to provide the procedure. I am just aware that the panels are up to it straight from the horse's mouth!

Don't forget a good heat tension treatment at the same time.

[thekid]

Congrats on the find!
I doubt I will ever come across a pair in the thrifts but you never know..... :D

They certainly look sturdier than Magnapans.
How does their sound compare?

[E-Stat]

They certainly look sturdier than Magnapans.
With the panels themselves, there really isn't anything to break so long as the diaphragms aren't punctured. The voice coil wires on Maggies can delaminate from the diaphragms after a long period of time.


How does their sound compare?
They are certainly similar as dipoles although I think only the Acoustats are true line sources. I had Maggies before my first set of Acoustats in the late 70s. Their advantage is coherence - as they are a true full range design. There are no frequency specific parts to the panels. On the flip side, however, their reactive load requires a beefy amp. The trusty '81 Threshold was designed to drive the notoriously difficult load of the Dayton-Wright electrostatic and works well with Acoustats.

The 1+1s compare to the 1.6/1.7 design but have a bit more radiating area with their 94" height: 830 sq in vs. 550.

[JoeE SP9]

Comparing the sound of Acoustats to Magnepans is easy for me. I sold my (then) MGIII's when I heard a a pair of Acoustat Model 3's in 1983. I've had nothing but esl's in my room since then.

IMO there is no comparison, esl's sound better.

[thekid]

Joe/E

Thanks for answering my questions.I really like my MMG's but will now add these to my watch list. You never know what might show up on Craigslist.......

[JoeE SP9]

Dipolars including Magnepans, Apogee ribbons and various esl's are the only speakers I really want to listen to. When guests ask about my esl's I usually recommend Magnepan MMG's and a sub woofer as their best option.

I could live with any of Magnepan's products although MMG's would have to have a sub woofer.
Having two 12" transmission line subs has spoiled me.

[TM3]

Hi guys,

I recently acquired a set of acoustat mk 121-2 and am searching for information on them. Seems like there might be people here with experience.

They are in good condition, some very light pilling in some spots but overall pretty clean. I have no experience with electrostatic speakers, and not sure if I have room for these in the long run but figured I would try them out. I have an receiver laying around that I think I can use to run them, is there any dos or donts when it comes to using these?

[E-Stat]

I recently acquired a set of acoustat mk 121-2 and am searching for information on them. Seems like there might be people here with experience.
You've come to the right spot. There are a few of us here who have owned them for decades. Actually, the model number you mentioned describes the power supply but was shared by different models based upon the panel configuration.

Here's a list of a few of them:

1 - single panel
1+1 - two panels, one stacked upon the other (above)
2 - two panels side by side
2+2 - two panels wide by two tall
3. - three panels across
4 - four panels across
6 - three panels wide by two tall
8 - four panels wide by two tall

What is their height and width? That will tell you the actual model.


I have no experience with electrostatic speakers, and not sure if I have room for these in the long run but figured I would try them out. I have an receiver laying around that I think I can use to run them, is there any dos or donts when it comes to using these?
I'll start with the bad news:

1. They are inefficient
2. They beam. That is to say the sound field changes from side to side.
3. They present a challenging load to the amplifier and most receivers really aren't designed to drive them.
4. Once every year or so, you'll need to heat treat the panels with a hair dryer as the mylar diaphragm will stretch over time.
5. The company is no longer in business.

The Good News:

1. They are exceptionally coherent because they are essentially a single driver design. There are no frequency specific panels like you find in conventional speakers having woofers, midranges and tweeters
2. They are capable of high resolution and naturalness.
3. They provide a lifelike image height
4. While first octave bass response is rolled off on the smaller models, they have exceptionally natural timbre in the upper bass.
5. The panels are very durable and the speakers will last for decades.

Here is a website (http://www.audiocircuit.com/Home-Audio/Acoustat) with all sorts of information about them. You may be interested in the factory tour (scroll down a bit) which describes how they were built.

[TM3]

Thanks

They are 58" tall, 20" wide, 3.5" thick and have a slight backward tilted angle to them. They look like the model 2's on that website.

The receiver I have is an Onkyo TX-SV50pro. ONKYO TX-SV50-PRO SM Service Manual free download, schematics, eeprom, repair info for electronics (http://elektrotanya.com/onkyo_tx-sv50-pro_sm.pdf/download.html) Manual is available here "get manual" under the image.

I am not that much into high quality audio, and I don't really want to spend much to be able to use these. But if I could drive them with my receiver I am interested how they sound. Any estimates of what they are worth?

[E-Stat]

They are 58" tall, 20" wide, 3.5" thick and have a slight backward tilted angle to them. They look like the model 2's on that website.
That sounds right.


The receiver I have is an Onkyo TX-SV50pro.
Well, Onkyo typically does well with low impedance loads. As long as it runs OK and doesn't trigger the protection circuitry, you should be fine.


IBut if I could drive them with my receiver I am interested how they sound. Any estimates of what they are worth?
One other aspect of them is they are dipolar - that is to say they radiate the same sound from the rear. That means that distance to rear wall affects the sound. Ideally, you will be able to give them a couple of feet to "breathe" in the room. Too close to the wall and they will sound muffled and bass will suffer.

Worth? Depending upon condition, anywhere from $300 to $800 or so. They were about $1800 new.

[TM3]

That is my biggest problem. I just don't have the room to use them how they should optimally be used. I am going to try them out tonight and see how it works. Thanks for all the help

[JoeE SP9]

No one mentioned to TM3 that they need to be plugged in for a while to sound their best. They will sound flat harsh and grainy when just plugged in. If they're plugged in tonight they'll sound pretty good tomorrow. Tonight they probably won't sound that good.

[TM3]

They sound better than any other speakers I have. I am going to try to enjoy them for awhile but in the long run I just dont have the space for them

[JoeE SP9]

Be careful, they might spoil you for any other speakers. That's what happened to me.

[Florian]

Be careful, they might spoil you for any other speakers. That's what happened to me.

Sounds like Apogees or V12 cylinder cars :devil:

[E-Stat]

Bought five yards of black lycra spandex at the local Hancock Fabrics and took to alteration shop. Wanted beige or grey, but neither were available. Material cost: $65, labor: $40.

Looks much better up close than oldies and is more acoustically open. Next step, updating the power supplies...