I think possibly more than any other subject here, this is simply a matter of taste, not only encompassing electrostatics vs. point source, but also dipole vs. monopoles. I personally DONT care for Martin Logans (I also worked for them for a bit and they are a HORRIBLE company to work for), but I must admit I can appreciate their capabilities. I also dont care for dipoles in general, just give me a clean set of transparent two ways, BUT, some people love electrostatics, and ribbons, and dipoles, and I understand why, its just whatever speakers make you smile..... so listen alot and then decide.
ESL
Thats why I made a FINAL 1400 Clone. The Martin Logan is the best ESL I ever had, but the FINAL 1400 has the looks (Sounds really BAD!)The Audiostatics, all of them, sounds to hard, (listening fatigue) and the will stop working within a year or two, if you are lucky, otherwise sooner.
You really need to test/listen to all the comertial ESL's before you deside and/or criticize.
Please don't take this personally, I just want to say, listen and listen and listen and than listen and listen till you get enough of it! Than make a choice, but not before you had a tremendus BLIND TEST!
Best regards,
Audiofanatic
Thats why I made a FINAL 1400 Clone. The Martin Logan is the best ESL I ever had, but the FINAL 1400 has the looks (Sounds really BAD!)The Audiostatics, all of them, sounds to hard, (listening fatigue) and the will stop working within a year or two, if you are lucky, otherwise sooner.
You really need to test/listen to all the comertial ESL's before you deside and/or criticize.
Please don't take this personally, I just want to say, listen and listen and listen and than listen and listen till you get enough of it! Than make a choice, but not before you had a tremendus BLIND TEST!
Best regards,
Audiofanatic
E-stats have thier place
I am writing because i too am an e-stat lover.
I have had two sets now, and the first thing to realize is that there is a HUGE differnce between the two.
I have the Accustat Spectra 11 seris and a hybrid system, based on Sheldon Stoke's ESL designs.
Pro's Con's
1.) Sheldon Stokes ESL designs have a sweet spot that is UNBELIEVABLE. I have never been in as much "intense sound". If you feel intrigued hit this page up, this is the guy who designed and has made several sets of these that sound beutiful. This site will tell all. That being said, these pronounce the E-stat trait of not being party machines. These speakers are made to be pointed at a comfy chair in the room.
2.) On the Spectra 11s, these do not have quite the sweet spot of the others I have, but they perform better off axis then the other ones. This is not to say they perform at the level of cones, but darn close.
ESLs are enriching my life by the day. I can honestly that the e-stats have made me a bigger fan of music in general.
My mentor once told me right before I heard E-stats for the first time that 95% of people sit down and say cool. They get up 5 min later and can walk away. The other 5% will become addicted, and not want to get up unless they are off to build themselves a set.
So wanna build em?
http://www.quadesl.com/diy_esl1.shtml
Brian
I am writing because i too am an e-stat lover.
I have had two sets now, and the first thing to realize is that there is a HUGE differnce between the two.
I have the Accustat Spectra 11 seris and a hybrid system, based on Sheldon Stoke's ESL designs.
Pro's Con's
1.) Sheldon Stokes ESL designs have a sweet spot that is UNBELIEVABLE. I have never been in as much "intense sound". If you feel intrigued hit this page up, this is the guy who designed and has made several sets of these that sound beutiful. This site will tell all. That being said, these pronounce the E-stat trait of not being party machines. These speakers are made to be pointed at a comfy chair in the room.
2.) On the Spectra 11s, these do not have quite the sweet spot of the others I have, but they perform better off axis then the other ones. This is not to say they perform at the level of cones, but darn close.
ESLs are enriching my life by the day. I can honestly that the e-stats have made me a bigger fan of music in general.
My mentor once told me right before I heard E-stats for the first time that 95% of people sit down and say cool. They get up 5 min later and can walk away. The other 5% will become addicted, and not want to get up unless they are off to build themselves a set.
So wanna build em?
http://www.quadesl.com/diy_esl1.shtml
Brian
There are a couple of things that are often done wrong in home-brew and sometimes even in commercial electrostatics, such as assuming that voltage drive will give a flat response, neglecting interference effects between the sound coming from different parts of the diaphragm and insufficiently damping the diaphragm resonance. So I'm not surprised that some electrostatics sound bad.
I'm yet another e-stat lover. My first pair were 4 panel Acoustats. Despite poor imaging and an excuciatingly small sweet-spot, they were a revelation to me. When one died (was killed by a golden retriever) I went for several years till I could afford to rebuild my system around another pair of e-stats. Just couldn't go back. I just got some Martin Logan Prodigies. Detail, imaging, and "purity" are stunning and the sweet spot now encompasses both me and my sweety Their only problem is cost.
eStatic
Their only problem is cost.eStatic
Ah, if anything BUT a golden retriever had taken out one of my panels I would go ballistic. You gotta forgive the goldens though, they are way to happy to know what they are doing.
I would be interested to hear what commercial panels people have bought, and what they thought of the assosiated sound.
I would be interested to hear what commercial panels people have bought, and what they thought of the assosiated sound.
I bought a pair of second-hand QUAD ESL-63's in December 2001. They were ridiculously cheap (800 guilders per pair) because their dust covers are not in an optimal condition, causing some soft rattling noises when loud 55Hz or so sine waves are played. I never noticed this effect on music or speech signals.
For what it's worth, I like them very much. They sound very neutral to me and the stereo imaging is very good, enormously improved compared to the DIY dynamic boxes I used before.
Technically, they are also quite good, having an extremely flat far-field on-axis response and a gradually increasing directivity. Peter Walker knew exactly what he was doing when he designed them. In fact, he is the one who derived Walker's equation, a simple equation relating the far-field response of an electrostatic loudspeaker to the sum of the currents through the stator segments. Many ESL manufacturers still seem to be unaware of this relationship.
For what it's worth, I like them very much. They sound very neutral to me and the stereo imaging is very good, enormously improved compared to the DIY dynamic boxes I used before.
Technically, they are also quite good, having an extremely flat far-field on-axis response and a gradually increasing directivity. Peter Walker knew exactly what he was doing when he designed them. In fact, he is the one who derived Walker's equation, a simple equation relating the far-field response of an electrostatic loudspeaker to the sum of the currents through the stator segments. Many ESL manufacturers still seem to be unaware of this relationship.
Transients/ Electrostatics and conventional drivers
Ive used both and report Electrostatics are so charming
i dont think i could face a conventional speaker day in day out
Lack of distortion is really what makes transients reproduce.
Yes cone drivers slam and all of that, and can really project
sound, but intricate parts in music including transients require
the lowest distortion possible. The electrostatic is one of the
best speakers in this area I consider.
Cheers / Chris
Ive used both and report Electrostatics are so charming
i dont think i could face a conventional speaker day in day out
Lack of distortion is really what makes transients reproduce.
Yes cone drivers slam and all of that, and can really project
sound, but intricate parts in music including transients require
the lowest distortion possible. The electrostatic is one of the
best speakers in this area I consider.
Cheers / Chris
In Lynn Olson's articles anybody can read the following against electrostats:
"Pulse Coherent (3D-Imaging) is the only type of dynamics to offer accurate pulse reproduction, sometimes even bettering exotic electrostats or ribbon loudspeakers."
"these new horns, and the Edgarhorn in particular, are in a class
of their own, superior to ribbons, electrostats, planars, exotic dynamics,
etc."
"All of the electrostats I have measured show
moderate resonances below 200 Hz (primary room-diaphragm resonance) and
multiple sharp resonances above 8 kHz (non-homogenous diaphragm motion and
standing waves in the HV stators or metal grill-frame assembly."
"In
addition, a true ribbon offers some of the best treble around, superior to
dynamics or electrostats, exceeded only by the "massless" exotics(e.g Plasmatronics)"
"Overall Strengths of Rigid-Class Drivers (Eton, Focal, Audax, Excel)
Strengths are: Best available transparency, imaging, and depth presentation
of any type, equalling or exceeding electrostats if carefully designed.[...]"
"Magnetic-planar sound quality is usually midway between a good dynamic and
an electrostatic, with a significant freedom from cabinet colorations at
mid and high frequencies. Radiation pattern is similar to an electrostatic,
which means problems with imaging and bass, with the minimal amplifier
damping making some rooms unusable"
About ESLs also: "
There is a downside, of course, and that is very low efficiency, an
extremely reactive amplifier load, restricted dynamic range, fragility,
limited bass, and a tricky room-sensitive dipolar radiation pattern that
becomes quite directive at high frequencies. These problems are not easy to
solve, particularly the large-panel dispersion, which is not an asset, but a serious problem for stereo imaging.
In short, wonderful midrange and depth perspective, and good-but-not-great at the frequency extremes , reasonable-to-fair stereo imaging , and somewhat
limited dynamic range ."
Can anyone shed some light here especially in the bold-underlined cons of ESLs?
Is it because he has constructed the Ariels and claims that they can surpass even the electrostats?
Thanks,
Michael
Some of what he says is valid, some is valid sometimes but not always, some is just pure opinion, and some is absolute doo-doo. It's best to take the scratching of audio writers with a large grain of salt, especially when they're selling or promoting competitive products.
There's no substitute for going out and listening. And it's always best to be cautious about generalizing from the particular.
There's no substitute for going out and listening. And it's always best to be cautious about generalizing from the particular.
I think it's been known for some time that cones can be "faster" than electrostatics. I remember reading an article in Audio magazine some time ago about some frustrated loudspeaker designer saying, "But we're faster, dammit,,,,"
Apparently the way it works is that the cone diaphragms are heavier, but the magnetic system can produce much more force than the electrostatic system to move the diaphragm. I think Roger Sanders says the electrostatic system only produces about one fifth the force that magnetic systems can produce.
However, there is another factor. I remember reading an article and the loudspeaker designer said that the problem with cones is that one frequency sounds like it is coming from one spot, a higher frequency sounds like it is coming from a spot several feet back.
Another article went into details, though I forgot those details. The thrust was that dynamic drivers have time delay between frequencies because they are inductive.
I realize that electrostatics are capacitive, and time delay can occur there as well, but apparently it seems to be less of a problem.
If anyone knows about that time delay between frequncies thing, by all means let me know. As I said before, I forgot the details of how it works, only that it does affect the sound.
Apparently the way it works is that the cone diaphragms are heavier, but the magnetic system can produce much more force than the electrostatic system to move the diaphragm. I think Roger Sanders says the electrostatic system only produces about one fifth the force that magnetic systems can produce.
However, there is another factor. I remember reading an article and the loudspeaker designer said that the problem with cones is that one frequency sounds like it is coming from one spot, a higher frequency sounds like it is coming from a spot several feet back.
Another article went into details, though I forgot those details. The thrust was that dynamic drivers have time delay between frequencies because they are inductive.
I realize that electrostatics are capacitive, and time delay can occur there as well, but apparently it seems to be less of a problem.
If anyone knows about that time delay between frequncies thing, by all means let me know. As I said before, I forgot the details of how it works, only that it does affect the sound.
I would point out not just about electrostatics, but all large planar style speakers: a large diaphragm means less intermodulation distortion, especially at loud frequencies.
Whenever a lower frequency is produced, the diaphragm must move a certain amount-the lower and louder the frequency, the more it must move. When higher frequencies are produced as well, sum-and-difference frequencies are generated.
The amplitude of sum-and-difference frequencies are directly proportional to the amount the diaphragm moves. It sounds like mud, and is very audible. In some speakers, when played loud enough, the sum-and-difference frequencies are just as loud as the fundamental frequencies of the music!!
The larger the diaphragm, the less it must move to produce any lower or midrange frequency, and therefore the lower the amplitude of the sum-and-difference frequencies. I do believe that is much of the appeal of large planar speakers, whether moved by electrostatic means or other.
Whenever a lower frequency is produced, the diaphragm must move a certain amount-the lower and louder the frequency, the more it must move. When higher frequencies are produced as well, sum-and-difference frequencies are generated.
The amplitude of sum-and-difference frequencies are directly proportional to the amount the diaphragm moves. It sounds like mud, and is very audible. In some speakers, when played loud enough, the sum-and-difference frequencies are just as loud as the fundamental frequencies of the music!!
The larger the diaphragm, the less it must move to produce any lower or midrange frequency, and therefore the lower the amplitude of the sum-and-difference frequencies. I do believe that is much of the appeal of large planar speakers, whether moved by electrostatic means or other.
I noted some substantial differences in opinion and some misunderstandings...
Here's my take:
- ESLs *greatest* benefit, especially full range cells, comes from the *harmonic signature* being identical all the way up and down the reproduced spectrum. Unlike dynamic speakers where you are switching between and mixing between often completely different materials (driver cones), ESLs have a uniform spectra of distortion products up and down the band. (think about why this is audible...)
It is true that you can get a similar result with a true single driver (Bandor, Jordan, or other wide range single driver) and with a planar or ribbon driver (to some extent). But the question is which drive system will produce the most uniform result with the least distortion over the widest range.
- "Speed" is a misnomer - there is no such parameter. What we feel or hear as speed is frequently something else entirely. In reality the "speed" of a system or driver is directly related to the highest frequency that can be reproduced, and nothing more.
If you want to talk about the subjective "feel" of speed, then we're talking things like HF distortion on peaks (yes), ringing and overshoot (Q), and even non-linearity (especially tweeters). Also playing a role is the on axis response vs the power response.
- All speakers are a compromise. There is no free lunch. The better the system is made, no matter what the technology, the *less* difference can be heard between a comparison of said speakers of extremely SOTA quality. (quality, not price) So, you have to chose your compromises.
- Wide frequency response and high output levels can be accomplished with ESL technology. The question is can you accept the compromises? They are *large size*, *big amplification*.
BTW, I have a friend who has owned Audiostatics for many years, and they seem to work fine, sound wonderful - equal to the quality of what goes in actually. So, one needs to be aware that one thing for certain, you will hear any grunge or nasties that the signal chain inputs to an ESL. This has caused some people to think that it was the speaker that was responsible - usually not.
MLs don't have good bass - add some subs (see pix on my website for example), and they're not my favs, subjectively too "polite" but that can be traced to certain design compromises.
Quad 57s - masterful execution, wonderful as a small room speaker, wonderful for voices, lacks in the extremes and w/spl. The 63s, never my cup of tea, but polite generally. (aren't all British speakers kinda "polite"??) The big Sound Labs, sound big and pretty good, maybe lacking a little in imaging, but perhaps that was just the set up I heard. Etc... all yin/yang compromises...
Oh, heard Roger Sander's stuff at a show a few years back, and it sounded pretty good at the show.
In general, most ESLs are *lower* in distortion than *most* dynamic drivers when played at moderate listening levels - not withstanding what Lynn Olsen says (didn't read it...) - after that it is all a question of personal preferences and which compromises float your boat.
FYI, I listen to big horns, ESLs and dynamic speakers here... I've heard a really wide range of the commercial high-end systems over the last 35 years now. Some have been heard to good advantage, some have not. Some have sounded awful at one time in one place and sounded quite nice at another time and place. Be careful not to draw too many conclusions from a relatively small sampling... and, at most shows the rooms sound horrid, no matter how expensive the gear. Oh, nothing comes close to the "jump factor" of my horns.
Here's my take:
- ESLs *greatest* benefit, especially full range cells, comes from the *harmonic signature* being identical all the way up and down the reproduced spectrum. Unlike dynamic speakers where you are switching between and mixing between often completely different materials (driver cones), ESLs have a uniform spectra of distortion products up and down the band. (think about why this is audible...)
It is true that you can get a similar result with a true single driver (Bandor, Jordan, or other wide range single driver) and with a planar or ribbon driver (to some extent). But the question is which drive system will produce the most uniform result with the least distortion over the widest range.
- "Speed" is a misnomer - there is no such parameter. What we feel or hear as speed is frequently something else entirely. In reality the "speed" of a system or driver is directly related to the highest frequency that can be reproduced, and nothing more.
If you want to talk about the subjective "feel" of speed, then we're talking things like HF distortion on peaks (yes), ringing and overshoot (Q), and even non-linearity (especially tweeters). Also playing a role is the on axis response vs the power response.
- All speakers are a compromise. There is no free lunch. The better the system is made, no matter what the technology, the *less* difference can be heard between a comparison of said speakers of extremely SOTA quality. (quality, not price) So, you have to chose your compromises.
- Wide frequency response and high output levels can be accomplished with ESL technology. The question is can you accept the compromises? They are *large size*, *big amplification*.
BTW, I have a friend who has owned Audiostatics for many years, and they seem to work fine, sound wonderful - equal to the quality of what goes in actually. So, one needs to be aware that one thing for certain, you will hear any grunge or nasties that the signal chain inputs to an ESL. This has caused some people to think that it was the speaker that was responsible - usually not.
MLs don't have good bass - add some subs (see pix on my website for example), and they're not my favs, subjectively too "polite" but that can be traced to certain design compromises.
Quad 57s - masterful execution, wonderful as a small room speaker, wonderful for voices, lacks in the extremes and w/spl. The 63s, never my cup of tea, but polite generally. (aren't all British speakers kinda "polite"??) The big Sound Labs, sound big and pretty good, maybe lacking a little in imaging, but perhaps that was just the set up I heard. Etc... all yin/yang compromises...
Oh, heard Roger Sander's stuff at a show a few years back, and it sounded pretty good at the show.
In general, most ESLs are *lower* in distortion than *most* dynamic drivers when played at moderate listening levels - not withstanding what Lynn Olsen says (didn't read it...) - after that it is all a question of personal preferences and which compromises float your boat.
FYI, I listen to big horns, ESLs and dynamic speakers here... I've heard a really wide range of the commercial high-end systems over the last 35 years now. Some have been heard to good advantage, some have not. Some have sounded awful at one time in one place and sounded quite nice at another time and place. Be careful not to draw too many conclusions from a relatively small sampling... and, at most shows the rooms sound horrid, no matter how expensive the gear. Oh, nothing comes close to the "jump factor" of my horns.
Thanks, Bear. I couldn't agree more with your comment about the notion of "speed." You can talk about rise time, which some equate with speed, but as you said, that's just a time domain version of the frequency domain notion of high frequency response. Anything that tops out at 20KHz is equally "fast" by this measure.
You can talk about fall time, or decay time. Devices not hampered by resonances will track the input signal in time and not release stored energy at some time long after the original electrical stimulus has disappeared. Some will describe their sound as "fast." Properly damped woofers behave this way, for example, and are sometimes confusingly described as "fast."
I personally believe that the low level of energy storage typically exhibited by an ESL operating at midrange frequencies is one of the key reasons they sound as they do. That, combined with the low intermodulation distortion that was mentioned as well, yield the magical ESL clarity. That's just an unproven guess on my part.
I'm still unsure of the role of coherence in all this. I'm drawn to speakers that can accurately reproduce a square wave or impulse, but I can't swear it's because I can hear a difference. I just like the idea of not mucking up the waveform. Linear phase devices may also sound "faster" as a result of the coherent reproduction of transients but, as I said, I can't swear I've heard it. They sure look better--and maybe even "faster"--on an oscilloscope!
You can talk about fall time, or decay time. Devices not hampered by resonances will track the input signal in time and not release stored energy at some time long after the original electrical stimulus has disappeared. Some will describe their sound as "fast." Properly damped woofers behave this way, for example, and are sometimes confusingly described as "fast."
I personally believe that the low level of energy storage typically exhibited by an ESL operating at midrange frequencies is one of the key reasons they sound as they do. That, combined with the low intermodulation distortion that was mentioned as well, yield the magical ESL clarity. That's just an unproven guess on my part.
I'm still unsure of the role of coherence in all this. I'm drawn to speakers that can accurately reproduce a square wave or impulse, but I can't swear it's because I can hear a difference. I just like the idea of not mucking up the waveform. Linear phase devices may also sound "faster" as a result of the coherent reproduction of transients but, as I said, I can't swear I've heard it. They sure look better--and maybe even "faster"--on an oscilloscope!
One of my fav causes is the idea of harmonic coherency...
Of course if the distortion is low, and the bandwidth is wide or properly balanced, that also helps to make for a good sounding speaker.
It's just my observation, but I think this idea that I'm calling harmonic coherency or integrity is the key to understanding the attraction of the single wide range driver, like the Lowther, to many.
It's fairly intuitive and simple to understand why a piano note (for example) whose fundamental is *above* the xover between a woofer and a mid (especially those made of radically different materials) will *automatically* have an audibly different sound, as
compared to the piano note that falls within the woofer's range + the midrange's range...
It's quite obvious that no matter how good that multi way, multi material system is, that it can't possibly be as consistent as will a piece of mylar that reproduces the entire spectrum in terms of the way that harmonics stack up across the spectrum.
This, I think is the main attraction of the single dynamic driver... and actually a true benefit.
Clearly the Quad 57 was and is one of the best speakers to maintain a sense of this integrity in a multi way speaker (3 way). I think it suceeds in large measure due to outstanding engineering and design, plus the benefit of having all of the driven surfaces made from the same material (mylar).
ESLs in general maintain a very good "harmonic integrity" while
also managing to have generally faster decay times, which translates into what ELS lovers appreciate most, imho.
This is no panacea, but I think the idea plays a role in how people perceive the sound from speakers and is a significant part of why there is a big subjective difference between the various different speaker methodologies and techniques.
_-_-bear
Of course if the distortion is low, and the bandwidth is wide or properly balanced, that also helps to make for a good sounding speaker.
It's just my observation, but I think this idea that I'm calling harmonic coherency or integrity is the key to understanding the attraction of the single wide range driver, like the Lowther, to many.
It's fairly intuitive and simple to understand why a piano note (for example) whose fundamental is *above* the xover between a woofer and a mid (especially those made of radically different materials) will *automatically* have an audibly different sound, as
compared to the piano note that falls within the woofer's range + the midrange's range...
It's quite obvious that no matter how good that multi way, multi material system is, that it can't possibly be as consistent as will a piece of mylar that reproduces the entire spectrum in terms of the way that harmonics stack up across the spectrum.
This, I think is the main attraction of the single dynamic driver... and actually a true benefit.
Clearly the Quad 57 was and is one of the best speakers to maintain a sense of this integrity in a multi way speaker (3 way). I think it suceeds in large measure due to outstanding engineering and design, plus the benefit of having all of the driven surfaces made from the same material (mylar).
ESLs in general maintain a very good "harmonic integrity" while
also managing to have generally faster decay times, which translates into what ELS lovers appreciate most, imho.
This is no panacea, but I think the idea plays a role in how people perceive the sound from speakers and is a significant part of why there is a big subjective difference between the various different speaker methodologies and techniques.
_-_-bear
Quote:
"There is a downside, of course, and that is very low efficiency, an extremely reactive amplifier load, restricted dynamic range, fragility, limited bass, and a tricky room-sensitive dipolar radiation pattern that becomes quite directive at high frequencies. These problems are not easy to
solve, particularly the large-panel dispersion, which is not an asset, but a serious problem for stereo imaging.
In short, wonderful midrange and depth perspective, and good-but-not-great at the frequency extremes , reasonable-to-fair stereo imaging , and somewhat
limited dynamic range ."
Electrostats are definitely not suitable as PA loudspeakers for rock concerts. Many of them can produce enough sound for a normal living room, though.
Large flat-panel electrostats where the entire stators are directly driven by the transformed amplifier voltage are extremely capacitive, have little bass and become extremely directional at high frequencies. But these things can all be solved by using a current-driven multiway system, like the original QUAD ESL, or a damped transmission line system, as used in the QUAD ESL-63, ESL-988 and ESL-989.
A dipole radiation characteristic has advantages as well as disadvantages. According to the late Peter Baxandall, it is advantageous to have somewhat directive loudspeakers to improve stereo imaging, but at the same time, the radiation pattern should stay essentially the same up to 1kHz or so to prevent unnatural colouring of the reverberation. This means that the loudspeakers should also be directive for very low frequencies, which means that you either need extremely large loudspeakers or dipoles.
Dipoles excite less room resonances than omnidirectional loudspeakers. This is an advantage when the most annoying resonances are not excited. On the other hand, it also means that the frequency above which the resonances are so close together that they sound like uniform reverberation becomes higher, which is a disadvantage...
"There is a downside, of course, and that is very low efficiency, an extremely reactive amplifier load, restricted dynamic range, fragility, limited bass, and a tricky room-sensitive dipolar radiation pattern that becomes quite directive at high frequencies. These problems are not easy to
solve, particularly the large-panel dispersion, which is not an asset, but a serious problem for stereo imaging.
In short, wonderful midrange and depth perspective, and good-but-not-great at the frequency extremes , reasonable-to-fair stereo imaging , and somewhat
limited dynamic range ."
Electrostats are definitely not suitable as PA loudspeakers for rock concerts. Many of them can produce enough sound for a normal living room, though.
Large flat-panel electrostats where the entire stators are directly driven by the transformed amplifier voltage are extremely capacitive, have little bass and become extremely directional at high frequencies. But these things can all be solved by using a current-driven multiway system, like the original QUAD ESL, or a damped transmission line system, as used in the QUAD ESL-63, ESL-988 and ESL-989.
A dipole radiation characteristic has advantages as well as disadvantages. According to the late Peter Baxandall, it is advantageous to have somewhat directive loudspeakers to improve stereo imaging, but at the same time, the radiation pattern should stay essentially the same up to 1kHz or so to prevent unnatural colouring of the reverberation. This means that the loudspeakers should also be directive for very low frequencies, which means that you either need extremely large loudspeakers or dipoles.
Dipoles excite less room resonances than omnidirectional loudspeakers. This is an advantage when the most annoying resonances are not excited. On the other hand, it also means that the frequency above which the resonances are so close together that they sound like uniform reverberation becomes higher, which is a disadvantage...
I've come late to this discussion, but here's my twopenn'orth. Elecetrostatics are very nearly perfect transducers. Their moving mass is comparable with the mas of air they drive. It is possible to make electrostatic loudspeakers with comparable distortion to good amplifiers. Electromagnetic loudspeakers have so many fundamental flaws that it's hard to know where to start, but cone break-up and non-constant Bl factor might be two places. On the other hand, the electromagnetic loudspeaker is as well-developed as the internal combustion engine, so many of its flaws can be worked around. And it's cheap because it can be mass-produced. Conceptually, an electrostatic is extremely simple. Making one work is hard. Making two identical is harder. Making lots work that are nearly identical (commercial product) is really hard.
Dear hilbren .. re your amp
Your amp may benefit to have either a transformer output
( rare as ... ) or a capacitor driving the ESL .. normally
capacitors with amps are forbidden in audio nirvana .. but
the ESL, I consider is an interesting exception. Look at
the success of the Quad 11 ( transformer coupled ) or
Quad 303 ( capacitor coupled ) into Quad ESL57's , either
amp are a great combination. The coupling does make
an important difference to the sound and ability of driving
an ESL
An output capacitor or transformer provides a 90degree change where current then precedes voltage. Have a look at a Quad 303
schematic and yes it is a single rail (observing the contribution
of that amps regulator ) design forcing half rail voltage
on the output .. the Quad 303 uses an outrageous 2200uf
to block this DC and at the same time pass the audio
signal . It sounds terriffic into the Quad 57 ESL. An output
capacitor may be the answer to your problems .
Some amps are unstable driving large capacitive loads
so take care with this, you might want to ask other
contibutors to the forum about your particular model
of amp and its ability into capacitive load driving ESL's
The coupling of an ESL using a capacitor from what I know
and have tried ( Quad 303 and 405) is actually kinder on
an amp than directly ( normally ) connecting an ESL to an
amplifier.
Cheers / Chris
Your amp may benefit to have either a transformer output
( rare as ... ) or a capacitor driving the ESL .. normally
capacitors with amps are forbidden in audio nirvana .. but
the ESL, I consider is an interesting exception. Look at
the success of the Quad 11 ( transformer coupled ) or
Quad 303 ( capacitor coupled ) into Quad ESL57's , either
amp are a great combination. The coupling does make
an important difference to the sound and ability of driving
an ESL
An output capacitor or transformer provides a 90degree change where current then precedes voltage. Have a look at a Quad 303
schematic and yes it is a single rail (observing the contribution
of that amps regulator ) design forcing half rail voltage
on the output .. the Quad 303 uses an outrageous 2200uf
to block this DC and at the same time pass the audio
signal . It sounds terriffic into the Quad 57 ESL. An output
capacitor may be the answer to your problems .
Some amps are unstable driving large capacitive loads
so take care with this, you might want to ask other
contibutors to the forum about your particular model
of amp and its ability into capacitive load driving ESL's
The coupling of an ESL using a capacitor from what I know
and have tried ( Quad 303 and 405) is actually kinder on
an amp than directly ( normally ) connecting an ESL to an
amplifier.
Cheers / Chris