Electrostatic Speakers

Can anyone tell me the weaknesses of electrostatic speakers? I am currently considering soundlab speakers, but may purchase the Watt Puppy Sevens. I am aware of size and foot print limitations.
Virtually every type of speaker has its own set of problems. With electrostatics, the usual drawbacks can include:
1. a "plastic" coloration to the music (or great clarity, if you prefer electrostatics);
2. often inefficient and more difficult to drive than dynamic/cone speakers;
3. the main panel does not usually do a good job reproducing the deep bass frequencies (it must be very large to move enough air for deep bass), and thus often requires the use of a dynamic woofer/subwoofer, which is often hard to smoothly integrate (because the electrostatic panel is much faster than the dynamic cone of the woofer);
4. potential problems with "floor bounce" of the radiated sound, because the panel extends so close to the floor;
5. problems caused by dipolar radiation (ranges from mild to severe depending on the room and the amount of acoustic room treatment);
6. a tendency for flat panel statics to have moderate to severe "venetian blind" effect (limited vertical dispersion) and a small sweet spot (limited horizontal dispersion) which can range from mild to "head in a vice";
7. sound staging anomalies due to rear wave propagation (in severe cases, this can produce phantom images that appear to come from places well outside the regular sound pattern).

Having now listed the possible downsides of 'statics, I should also add that a good electrostatic can produce absolutely glorious sound. The best electrostatics, however, tend to be large and expensive, and thus may not suitable for many listening rooms (particularly small rooms). However, some of the smaller electrostatics and planars such as the Maggie 1.6R can produce some stunning music for a relatively modest cost. (So you know, I once owned a pair of Acoustat Model 2's which I loved, but I had to accept their limitations, and eventually got tired of them being them essentially being a 1-person speaker.)

Some of the newer generation of electrostatics have effectively addressed many of the more aggravating aspects of design, such as using a curved panel (introduced by Martin-Logan with the "CLS" series about 12 years ago).

More than any other speaker type, you should audition an electrostatic in your home and with your system.
Weaknesses: dipolar dispersion pattern isn't capable of the most accurate imaging/pinpoint. You also have to sit 2.5 to 3 times the panel heigth back (this may or may not be a weakness). Obviously, narrower dispersion as frequency increases: beaming. (can be like a giant pair of headphones in the room) More generally (so not always true): ampl. v. freq. resp. tend to not be very flat even on axis(+/-4db)(off-axis was already accounted for), tend to lack good damping/restoring forces so the waterfalls/cumulative spectral decay's can have alot of overhang. Ideally, more specifically, they wouldn't have the impedence matching transformer so they could be directly driven with an output transformerless tube amp--so most commercial versions are already compromised if your driving off a "regular" amp and its got the impedence matching transformer. And under those conditions they are generally a "tough" load; and as impedence drops the amplifier's distortion goes up (although small). Also, there can be reflections off the panel's edges--depends on how the manufacturer may or may not have tried to deal with that: sometimes a foam strip along edge. Also, I believe general placement is more done by ear, since most of the speaker placement programs and general rules-of-thumb don't work with dipolars. I've also seen units designed to diffuse/diffract the backwave from the esl. I don't know if their benefits justify the price, or improve performance enough to justify them as being: essential components. Lastly, and esl owners would know this, I don't know if some type of power conditioning is truly beneficial at times since the speakers do have to be plugged into polarize the panel: hence a dirty signal may do some damage.
I must say, these are two of the most informative and knowledgeable responses I have ever received from this page. You guys seem to really know what you are talking about. Thanks! Incidently, if I purchased the soundlabs, I would be running them with a 75 Watt OTL. I also listen in a very small room, since paying low rent is the only way I can afford these high priced electronics.
Haydn_josef- I wouldn't even think of trying to power soundlabs with a 75 watt otl, the impedance swings would be VERY unpleasant-which is one of the weaknesses of electrostats. You most likely would get the best results with a speaker that has a nominal impedance of 8 ohms and fairly stable, ie it doesn't have huge swings like electrostats often do. Unfortunatly otl's and electrostats don't mate up well, something along the line of Talon, Piega or Kharma would do much more justice to your amp-although all of the fore mentioned speakers are cone type drivers(and are just a few of my favorites with OTL's-there are many more that I am sure will work good) or big clunky boxes-though I like my big clunky boxes :)
btw great posts so far; Sdcambell and Ezmerelda1
I considered Martin Logans for a long time. The treble was magical but one problem I found with them is they didnt like to go very loud. I was told by the salesman that the reason for this is that the tweeters compress and distort when pushed to hard.

I have always regrtted though that I never owned a pair of electrostatic speakers. Maybe its a good excuse for a second system.
I've owned electrostats for almost 15 years, starting with Acoustats, Martin Logans (3 models), and finally large AudioStatics. All of these speakers were nothing short of amazing with OTLs. In fact, I would suggest that OTLs are the only way to get the absolute best from an esl. It is true that I had the benefit of 140 watt OTL monoblocks. Given the fact that your 75 watt OTLs would only be about 3 dB lower in maximum spl, I would still suggest that you try them. You may find that they are more than up to the task. Yes, this system may give up some dynamics compared to better cone systems, but the midrange/top-end can be a revelation. Particularly in a smaller room, the power issue becomes even less of a concern.
As is always the case, auditioning a speaker with your amp is certainly the best way to dispel all concerns. Good luck in your audio search.
I agree with Jcbtubes. I have also owned many electrostats including Quad ESLs, Quad 63s, Acoustat Monitor 3s, Acoustat Model 4s, and 2 different vintages of Soundlab A1s. Although I agree that large electrostats do better in larger room, for some of the reasons outlined by others who have already responded, they have many virtues. They also typically present high impedance loads and hence do very well with OTLs. I ran triod Fourier OTL amps for a while with my Soundlabs and found that they performed better in every way compared to any large solid state amp I had previously used. OTL amps tend to produce more power with higher impediences which makes them ideal for electrostats. You may find that a moderate output OTL will do the job quite nicely. Electrostats have a number of sonic strengths and their share of weaknesses. Many of the aforementioned criticisms are valid, but electrostats can be magical as well. Strongly consider OTLs if you decide to purchase Soundlabs!
Just as there are well-engineered exceptions to general trends one might identify for box or horn or ribbon speakers, so too with electrostats. I'd like to highlight some of those exceptions to the trends identified by Sdcampbell.

"1. a "plastic" coloration to the music (or great clarity, if you prefer electrostatics)." In my experience this statement only applies to curved-panel electrostats, not to flat panel ones. There are two reasons for the "plastic" coloration - first, the curved panel is a vertical slice of an expanding cylinder so its tension is constantly changing as it moves forward (expands) and back (contracts); and second, such a design calls for an extremely thick diaphragm. This thick diaphragm actually does not do inner harmonic detail well, thus giving the illusion of clarity because the fundamental tones stand out more. Flat panel electrostats don't suffer from these problems.

"2. often inefficient and more difficult to drive than dynamic/cone speakers." This is certainly true! The exceptions are the highly efficient (but difficult to drive) InnerSound speakers, and the moderately efficient and fairly easy to drive Quads (in particular the originals).

"3. the main panel does not usually do a good job reproducing the deep bass frequencies (it must be very large to move enough air for deep bass), and thus often requires the use of a dynamic woofer/subwoofer, which is often hard to smoothly integrate (because the electrostatic panel is much faster than the dynamic cone of the woofer)." Hybrids are extremely difficult to get right, and in my experience have a hard time being competitive with a well-designed conventional or Maggie system of comparable cost. In my opinion electrostats work best when large enough to operate full range.

"4. potential problems with "floor bounce" of the radiated sound, because the panel extends so close to the floor." I have to disagree; the directional properties of electrostats minimize floor bounce relative to conventional systems.

"5. problems caused by dipolar radiation (ranges from mild to severe depending on the room and the amount of acoustic room treatment)." Dipolar radiation requires several feet behind the speakers for good sound, but room treatment is quite easy since: 1) the panels tend to have uniform directional properties and 2) dipoles put very little energy into the room's bass resonant modes. In my experience if they can be placed several feet out into the room, dipoles are much less room-dependent than monopole speakers.

"6. a tendency for flat panel statics to have moderate to severe "venetian blind" effect (limited vertical dispersion) and a small sweet spot (limited horizontal dispersion) which can range from mild to "head in a vice"". These statements are both true, but I would like to point out that a tall curved array of flat panels can give you an exceptionally wide sweet spot and correct timbre anywhere in the room.

"7. sound staging anomalies due to rear wave propagation (in severe cases, this can produce phantom images that appear to come from places well outside the regular sound pattern)." Any soundstaging anomalies arising from the rear wave are easy to deal with. The inherent coherence of an electrostat (especially a full-range model) gives it potentially superb soundstaging characteristics, with absolutely no boxy cues to detract from the experience.

Also, full-range electrostats are capable of excellent soundstaging and recreation of the feel of the hall, but a really good point source speaker can give more precise localization of sound images. That being said, the second-best imaging and soundstaging I ever heard was from a thirty grand electrostat (the best was from a thirty-five grand dynamic system).

Well this thread isn't supposed to be about the things elecctrostats do well, so I'll tell you the weaknesses I see. My comments will not apply to hybrids, but only to full-range models.

First, they are expensive, and dollar-for-dollar seldom offer the bass extension and maximum volume level of a good conventional system.

Second, they command a lot of real estate. They tend to dominate a room, and like to be positioned 4-8 feet or so out from the front wall.

Third, there is usually a significant hidden amplifier cost.

Fourth, they are hard to find to audition.

Fifth, without good amplification and set-up they can be lacking in dynamic impact relative to a good conventional or high-efficiency system.

Sixth, they are not very rugged physically and are more likely to be damaged in shipping (this hurts resale value).

About the only redeeming feature of electrostats is that they generally sound more natural than their competition, at least within their volume range.

Haydn josef, if the amps you are considering are Tenors, then I think they will drive current generation Sound Labs quite well in a small room, especially since the impedance is more friendly now. I have a customer who is using 80-watt OTL amps in a fairly small room to drive older, more difficult A-1's. His listening position is about six feet from the panels, and he gets enormous depth of image (I was just at his house last night). E-mail me for particulars if you'd like.

Best of luck to you in your quest!

I wish to congratulate Duke for his excellent response in putting the pros and cons of stators in the right perspective. I've been using various brands of stators in very different configurations for more than 35 years and have always come back to them, when I was tempted to go astray, because of their midrange rendering, which basically nothing really can come close to in lack of coloration, transient speed, homogenity, sound space and general transparency. Cheers,
Hey if duke says it will work I am sure it will, he has NEVER steered me wrong. Dukes posts are so helpful and detailed, he helped me out with a little basic room treatment and man what a difference-I will never second guess his opinion!

i have owned sound lab ultimite 1s , a-3s pristines , dynastats, martin logan cls, quest and so on. stats especilly sound labs offer sound that whips most all high end cone speakers . they are transparent , they sound pure, and full, with gobs of depth. the drawbacks i noticed with soundlabs are macro dynamics are not quite the best. they were plenty loud for me though. they also take up alot of room. the panels can also rattle when pushed to hard. i could live with a-3s or u1s till the end of time though. i would think if you just sit back and enjoy your music then 75 tube watts should be enough. if you blast them then look at another speaker not any stats. good luck and let us know what you get.
I am a huge fan of ribbons and stats. I also love the cones. Most of the points made need not be repeated by me.

I have not heard a speaker that reproduces tonality better than the SoundLabs (some as good, but none better). I also personally know someone that is successfully driving the large SoundLabs with a pair of your OTL's.

If the music you listen to is Classical or Jazz, I do not think you can do better than the SoundLabs. The Piega's, which I sell, would be quite comparable and are easily driven by the 75 watt Tenor OTL's. The Maggie's might be questionable with your amps. If hard rock is more your cup of tea, and "air movement" is what you want, the Wilson's do a great job of that.

Duke: Great job!!!
has anyone tried 2 pairs of levinson ml2s(2per side strapped togeather) I think you may form a differeny opinion regarding the use of otls especially with soundlabs because the ML2 can handle any impedence out there without breaking a sweat
Bsevans -

The problem that a solid-state amplifier has driving the Sound Labs is related to the high impedance in the bass.

You see, the Sound Labs present a ballpark 40 ohm load in the deep bass, decreasing to around 6 ohms at 500 Hz, then going back up to maybe 15 ohms before gradually decreasing to 2 ohms or so at the very top end. (Before January 2002, that midrange impedance dip was down to around 3 ohms, rather than 6 ohms - which was much more of a challenge for OTL amplifiers. The reason for the two-hump impedance curve is Sound Labs use two transformers - one for the bass, and one for the high frequencies.)

I would guess that strapped Levinson ML2's do something like 100 watts into 8 ohms (not sure how the math works out), and double that into 4 ohms. But, what about into 40 ohms? Because solid state amplifiers act as a voltage source, the power delivered goes down as the impedance goes up. So into a 40-ohm load, a "100-watt amp" solid-state delivers about 20 watts, and clips way before you think it should. On the other hand, it will sound very good up until the point where clipping sets in.

Generally speaking, tube amps are better at delivering power into a high impedance load, so a high quality medium-powered tube amp has a better chance of driving the Sound Labs than a comparable solid-state amp.

I'm a fan of Apogee, the cheap treats. The only criticism I agree with above is the hidden amp cost. The speakers are so cheap, though, what does it matter?
"arcing","anemic bass", and "metallic highs"....
Phase, seems a long time since you listened to any type of stators last, unless of course you're speaking from hearsay.
Modern stators do not have any of those characteristics you speak of and yes, they are generally phasecorrect (sic) and have better continuity than most....
Phasecorrect, "Arcing?"

"Anemic bass," you got to be kidding. One of the great sonic successes of the big Apogees are their deep bass that play seamlessly with the mids and highs.

For realistic acoustic bass, there is no better. Certainly, certain box speakers can produce more slam, which works for electronic bass reproduction. If that is solely your cup of tea, then by all means... but if you want to hear a cello, drum, acoustic bass, etc.. and you want it to smoothly integrate, it is here the large Apogee panels will excel.

"Metallic highs," If you have ever heard a Diva, Scintilla, Duetta, or Full Range, then that term wouldn't have occurred to you. In fact, I haven't heard anyone characterize the highs of Apogees as being "metallic."

"...." I suppose by this, you mean everything else...

I can't say anything about other panel speakers except that the ones I've heard do a better mid than any dynamic drive I've heard. It is true, they are all room dependent to varying degrees. Floor reflections can be simply nullified using a rug.

It is the speed of the ribbon or panel that defines fine texture in a voice or instrument that sets them apart. Apogees extend this speed and clarity to 30Hz and lower.

Muralman1, you are right of course, but this thread is not about planar speakers in general, I believe, but about electrostatic speakers. Cheers,
OOps, Darn, don't you wish we had the ability to delete our own posts. I've wanted to do that from time to time, and I am sure others have wanted me to do that.... Thanks Detlof. :)
I agree with the excellent threads mentions here, but I
I would like to share my 2 cents experience about my
martin logan quest, I own them for at least 10 years,
ONE OF THE WEAKNESS THAT I consider most is the placment,
especially if you dont have enough room, to keep on moving
them,For me they sound excellent when I played them on
low volume.My room is well padded so reflection was not
a problem, playing them in low volume helps to eliminate
the reflection.I use plinius sa 100 just about right with
the volume level I like. HONESTLY KRELL 200 watt at least
with cardas wiring and wadia cd player they sounds