Do you guys remember Roger Sanders? He still makes ESL-hybrids. Here's what he said on another forum:
"There is more to this issue of bass quality than just the amount of deep bass available. Not only is the quantity of electrostatic bass inadequate, but the QUALITY of electrostatic bass is dismal. Let me explain that statement.
One of the truly wonderful things about ESLs is their low Q behavior. By way of review, the engineering term "Q" refers to the "quality" of the sound with respect to control and damping.
In other words, a "low Q" driver exhibits very well-controlled behavior with fast transient response and without any overshoot and ringing. A "high Q"
driver is poorly controlled, has resonances, overshoots and rings after an electrical impulse, and has poor ("smeared") transient response.
It does not stop instantly as it should. Instead it vibrates for many cycles a relatively long time until it finally comes to a complete stop. It "rings" like a bell. This behavior adds extraneous frequencies to the original sound that corrupts it and makes it sound very unnatural.
The massless nature of an ESL means that it can accelerate instantly to follow the musical wave form. Even more importantly, the mass of the air around an ESL totally swamps the incredibly tiny mass of the ESL's diaphragm, so it cannot "ring" and resonate. [over damped] It simply stops instantly, which gives it great clarity, detail, and transient response.
This is like trying to ring a bell underwater. It won't ring because the mass of the bell is swamped by the mass of the water around it. It simply is no longer free to vibrate and ring.
Therefore an ESL has very low Q behavior. This is one of the reasons it sounds so "tight", "crisp", "quick", and can extract the most subtle details from the sound and reproduce transients flawlessly. Low Q ESLs simply sound more "real" than high Q drivers.
However, this wonderful, low Q behavior of an ESL does not apply in the bass. An ESL is built like a drum, which is an extremely high Q device. An ESL has a stretched, "springy" diaphragm. The diaphragm is relatively large, so couples with a large amount of air in the room.
Air has mass. The relatively large mass of the air to which it is coupled will cause the ESL to resonate like a drum at some low frequency based on the mass and spring rate (tension) of the diaphragm. In ESLs of typical size, this resonance occurs between 50 Hz and 100 Hz. Tap on the edge of any ESL and you will hear this resonance.
This is the fundamental resonance of the ESL. It is the only resonance in an ESL, but it is huge (typically 16 dB) and like all resonances, it is extremely high Q.
Being high Q, frequencies around the fundamental resonance will be very poorly controlled and have a large amount of overshoot and ringing. The sound in this region will therefore sound very different from the low Q sound of the ESL everywhere else in the audio bandwidth. The result of this high Q behavior is that the quality of electrostatic bass is flaccid, poorly controlled, sloppy, and boomy.
Yet another problem with ESL bass is that it is very non-linear. The fundamental resonance causes a large peak in the bass followed by a sharp drop in output below it.
Most full range ESL manufacturers allow this peak to persist in a desperate effort to get their ESL to sound "bassy." But the result is very non-linear bass response, with no truly deep bass output at all. It becomes a "one note wonder."
In short, electrostatic bass has inadequate output, poor frequency response with no deep bass frequencies, and its high Q behavior results in poor bass quality. Therefore, I don't consider electrostatic bass to be satisfactory for a high performance speaker."
"There is more to this issue of bass quality than just the amount of deep bass available. Not only is the quantity of electrostatic bass inadequate, but the QUALITY of electrostatic bass is dismal. Let me explain that statement.
One of the truly wonderful things about ESLs is their low Q behavior. By way of review, the engineering term "Q" refers to the "quality" of the sound with respect to control and damping.
In other words, a "low Q" driver exhibits very well-controlled behavior with fast transient response and without any overshoot and ringing. A "high Q"
driver is poorly controlled, has resonances, overshoots and rings after an electrical impulse, and has poor ("smeared") transient response.
It does not stop instantly as it should. Instead it vibrates for many cycles a relatively long time until it finally comes to a complete stop. It "rings" like a bell. This behavior adds extraneous frequencies to the original sound that corrupts it and makes it sound very unnatural.
The massless nature of an ESL means that it can accelerate instantly to follow the musical wave form. Even more importantly, the mass of the air around an ESL totally swamps the incredibly tiny mass of the ESL's diaphragm, so it cannot "ring" and resonate. [over damped] It simply stops instantly, which gives it great clarity, detail, and transient response.
This is like trying to ring a bell underwater. It won't ring because the mass of the bell is swamped by the mass of the water around it. It simply is no longer free to vibrate and ring.
Therefore an ESL has very low Q behavior. This is one of the reasons it sounds so "tight", "crisp", "quick", and can extract the most subtle details from the sound and reproduce transients flawlessly. Low Q ESLs simply sound more "real" than high Q drivers.
However, this wonderful, low Q behavior of an ESL does not apply in the bass. An ESL is built like a drum, which is an extremely high Q device. An ESL has a stretched, "springy" diaphragm. The diaphragm is relatively large, so couples with a large amount of air in the room.
Air has mass. The relatively large mass of the air to which it is coupled will cause the ESL to resonate like a drum at some low frequency based on the mass and spring rate (tension) of the diaphragm. In ESLs of typical size, this resonance occurs between 50 Hz and 100 Hz. Tap on the edge of any ESL and you will hear this resonance.
This is the fundamental resonance of the ESL. It is the only resonance in an ESL, but it is huge (typically 16 dB) and like all resonances, it is extremely high Q.
Being high Q, frequencies around the fundamental resonance will be very poorly controlled and have a large amount of overshoot and ringing. The sound in this region will therefore sound very different from the low Q sound of the ESL everywhere else in the audio bandwidth. The result of this high Q behavior is that the quality of electrostatic bass is flaccid, poorly controlled, sloppy, and boomy.
Yet another problem with ESL bass is that it is very non-linear. The fundamental resonance causes a large peak in the bass followed by a sharp drop in output below it.
Most full range ESL manufacturers allow this peak to persist in a desperate effort to get their ESL to sound "bassy." But the result is very non-linear bass response, with no truly deep bass output at all. It becomes a "one note wonder."
In short, electrostatic bass has inadequate output, poor frequency response with no deep bass frequencies, and its high Q behavior results in poor bass quality. Therefore, I don't consider electrostatic bass to be satisfactory for a high performance speaker."
The main resonance of a dipole ESL is heard only in the near field, that is, from a short distance, it does not form a sound wave, because the sound pressure created by a weak electrostatic field is not enough for this. In other words, the ESL has a too weak motor, so it cannot be a drum with its main resonance.
For ESL to be a drum, it must be hit with a real mallet, but not with an electrostatic field
.The fundamental resonance of an esl is actually very high. There are several ways to decrease the Q but it wont match a dynamic woofer most of the time. There are also some doubts about the sonic penalties of heavy damping regarding midd and high frequency response. My personal experience is that fullrange bass is ' wooly' and ill defined at the lowest frequencies I get kind of used to it unless I switch to a dynamic speaker. Then the poor bass becomes obvious. So it depends on your reference and personal taste.
The fundamental resonance can be excited by tapping your fingers on the membrane. The electrostatic driving force can do the same or even better. You can slam the membrane into the stators with electrostatic driving force. A suggestion that electrostatic driving force is too weak makes no sense.
It appears to me that some hybrid ESLs tension the diaphragm quite high, and segment the diaphragm to distribute its resonance across a wider bandwidth, and then uses this resonance energy to enhance the mid-bass output. This approach mitigates the dipole's mid-bass suckout and allows crossing the woofer in at a lower frequency. The resonance distortion remains but is spread out, so not as noticeable as a single large peak would be-- all in all; not a bad compromise.
Some bi-amplified hybrid designs tension the diaphragm lower, to obtain a lower resonance frequency, and then sets a crossover point at least one octave above the resonance, to avoid exciting it. Mid-bass suck-out is avoided with a wider panel or EQ'ing (easy to do with an active bi-amp design), or some combination thereof.
My own speaker uses this latter approach-- but with either approach, the diaphragm's resonance cannot be fully mitigated. The upsides to this approach are that the resonance is weaker, as it isn't being actively driven at resonance, and the resonance frequency is below the ear-sensitive midrange region, where it's less objectionable.
Even when an ESL is powered OFF, a woofer hitting a sympathetic note anywhere in the same room will excite the diaphragm to resonate and emit sound. This is easy to verify visually by observing light reflecting off the diaphragm's surface, and seeing the image go fuzzy when the resonance is excited. If fact, an ESL would make a very good microphone.
While I'm rambling; another bit of design trivia (not saying it's right or wrong, so draw your own conclusions):
I recall reading a post on this forum many years ago, which discussed wire-stator ESLs specifically, and the benefits of adding a felt pad or acoustic cloth on the rear stator, to dampen the diaphragm resonance. I will paraphrase a comment from that post which grabbed my attention:
"Rather than adding a dead material that doesn't contribute to output, wouldn't adding more wires, spaced closer together, achieve the same effect?" The discussion continued and suggested 30% open area might work well (I believe member "Few" posted that, but I'm old and senile, not sure)
That post prompted my recollection of a research paper by Panasonic Corp back in the 70's which showed that the optimal open area (i.e. highest acoustic output) for an ESL tweeter stator was 42%.
Most DIY builders, including me, were targeting for 50%-60% open area, but after reading the above post and the Panasonic paper, I reduced the open area percentage on all of my subsequent wire stator ESLs. I didn't try 30% but I did reduce it to 42%, with no added damping materials.
Some bi-amplified hybrid designs tension the diaphragm lower, to obtain a lower resonance frequency, and then sets a crossover point at least one octave above the resonance, to avoid exciting it. Mid-bass suck-out is avoided with a wider panel or EQ'ing (easy to do with an active bi-amp design), or some combination thereof.
My own speaker uses this latter approach-- but with either approach, the diaphragm's resonance cannot be fully mitigated. The upsides to this approach are that the resonance is weaker, as it isn't being actively driven at resonance, and the resonance frequency is below the ear-sensitive midrange region, where it's less objectionable.
Even when an ESL is powered OFF, a woofer hitting a sympathetic note anywhere in the same room will excite the diaphragm to resonate and emit sound. This is easy to verify visually by observing light reflecting off the diaphragm's surface, and seeing the image go fuzzy when the resonance is excited. If fact, an ESL would make a very good microphone.
While I'm rambling; another bit of design trivia (not saying it's right or wrong, so draw your own conclusions):
I recall reading a post on this forum many years ago, which discussed wire-stator ESLs specifically, and the benefits of adding a felt pad or acoustic cloth on the rear stator, to dampen the diaphragm resonance. I will paraphrase a comment from that post which grabbed my attention:
"Rather than adding a dead material that doesn't contribute to output, wouldn't adding more wires, spaced closer together, achieve the same effect?" The discussion continued and suggested 30% open area might work well (I believe member "Few" posted that, but I'm old and senile, not sure)
That post prompted my recollection of a research paper by Panasonic Corp back in the 70's which showed that the optimal open area (i.e. highest acoustic output) for an ESL tweeter stator was 42%.
Most DIY builders, including me, were targeting for 50%-60% open area, but after reading the above post and the Panasonic paper, I reduced the open area percentage on all of my subsequent wire stator ESLs. I didn't try 30% but I did reduce it to 42%, with no added damping materials.
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This is imho the best way to deal with the resonance problem. Crossing over at one octave above resonance is sufficient to make it inaudible, provided a well tuned notch filter and/or very steep crossover is used. I actually use the notch to make the filter slopes 4th order. With dsp that is easy those days. In practice this means a crossover frequency of 100-150Hz, perfect for coupling a dipole or ripole woofer that can be tuned for a Q of 0.5-0.7, giving excellent natural uncoloured bass. Additional benefit is that the max spl of the planar will increase a lot.
I do not use lower membrame tension btw, because the effect on lowering resonance frequency is very limited but the effect on max output is huge as lower tension severely limits the max excursion.
Martin Logan - among others - made attempts in this formula, but it proved to be not so good : the ESL and the woofer cone in BR did not married very satisfactorily, they always more or less sounded "separated, each one in his court", if I can say so...
I think that a Ripole formula and his filling-floating bass effect could conversely give interesting results with an ESL, If I rely on the tests we made with MG2.5, MG3.5 and little SMGb Magnepan speakers.
T
I'm not crazy about ML hybrid integration either. I abandoned boxed woofers in my hybrid ESL builds long ago, in favor of open-baffle dipolar bass.
My latest hybrid ESLs have really good panel/woofer integration. The system is 6-channel stereo using digital 4th order crossovers at 250Hz and 65Hz driving low-Q Eminence Kappalite 3012LF mid-bass woofers and a pair of Ripol subs.
The low-Q woofer isn't optimal for low bass output, but it doesn't need to be with the subs in play, and it blends very well with the near-zero Q stat panel, which was the priority.
My latest hybrid ESLs have really good panel/woofer integration. The system is 6-channel stereo using digital 4th order crossovers at 250Hz and 65Hz driving low-Q Eminence Kappalite 3012LF mid-bass woofers and a pair of Ripol subs.
The low-Q woofer isn't optimal for low bass output, but it doesn't need to be with the subs in play, and it blends very well with the near-zero Q stat panel, which was the priority.
Majestic 945PX
The Majestic 945PX has been affectionately referred to as the Storm Speaker since it can capture sounds as delicate as a rain drop in life-like clarity as well as reproduce sounds as powerful as thunder claps with astonishing realism. When it comes to music, theres never been a speaker available that provides such listening pleasure. Big, bold and beautiful, the Majestic 945PX is a perfect combination of form and function.
Specifications:
Frequency response:
24 Hz to ultrasonics
Audio power (min/max):
50/600 watts (music power)
Radiating area:
3125 square inches
Horizontal dispersion:
45 degrees (full spectrum)
Vertical dispersion:
Projected field of panel height
Impedance (nominal):
8 ohms
Sensitivity:
89 dB/1W/1m
Bias power supply:
117/230 VAC, 50/60 Hz, 2 watts
Controls:
High frequency
Mid frequency
Bass level
D.C. Bias
Height x Width x Depth:
106″ x 39 3/4″ x 8 1/4″ (26″ at base)
Weight (per speaker):
221 pounds
Finishes:
Medium oak is standard
other finishes available)
The Majestic 945PX has been affectionately referred to as the Storm Speaker since it can capture sounds as delicate as a rain drop in life-like clarity as well as reproduce sounds as powerful as thunder claps with astonishing realism. When it comes to music, theres never been a speaker available that provides such listening pleasure. Big, bold and beautiful, the Majestic 945PX is a perfect combination of form and function.
Specifications:
Frequency response:
24 Hz to ultrasonics
Audio power (min/max):
50/600 watts (music power)
Radiating area:
3125 square inches
Horizontal dispersion:
45 degrees (full spectrum)
Vertical dispersion:
Projected field of panel height
Impedance (nominal):
8 ohms
Sensitivity:
89 dB/1W/1m
Bias power supply:
117/230 VAC, 50/60 Hz, 2 watts
Controls:
High frequency
Mid frequency
Bass level
D.C. Bias
Height x Width x Depth:
106″ x 39 3/4″ x 8 1/4″ (26″ at base)
Weight (per speaker):
221 pounds
Finishes:
Medium oak is standard
other finishes available)
I built some planer magnetic woofer panels once with no tension as reference for comparing to some other tensioned planer designs I was working on . It was a heavy, thick (laminated foil/ eurathane/foil ,about 3X normal mass of planers) nearly self supporting diaphragm. Close mic was flat below 20hz. The heavy thicker construction was nessasary in the smallish (12 inch X 36 in) diaphragms as that was how I quieted the diaphragms resonance issues without tension. I was able to get Fs on lighter tensioned diaphragms of same size this low BUT the very low tension resulted in no controll at Fs and ugly standing wave activity in the 100-400 hz range. What was interesting was the sound difference. The thick heavy well damped no tension planer woofer sounded very much like a really well damped IB box but without the boxy color. It was very dynamic sounding bass as in no boxy smear or color with fast decay. It sounded real. Problem is its sensativity was pathetic and thats saying it nicley. In the end I was able to get the tensioned film designs to sound similar but not quite. Largly this was done by adjusting the open area between mags and perferated plate. I had to get down to about 10 % open area to taim the large rise at Fs to a level that sounded similar to the heavy weight no tension units.
You can go low with tensioned film diaphragms BUT you will need a big one so that firm tension doesnt result in a high Fs. IMO a bunch of small maybe 7 inch low mass cones run open baffle is better way to do it if only going to around 400 hz or less
Mass matters and I noticed on the super light weight protos ( 3 micron mylar and 4 micron foil) the bass just did not have the authority and power of the higher mass units (usually 12 micron mylar and 18-30 micron foils). I mention this because some here have mentioned the double diaphragmed stats bass being great. I was talking with the designer of the "Gold Ribbon" once and he said the best bass hes heard was the double diaphragmed stats. He said the issue was mass mostly. Said when the diaphragm is this light the weight of the air mass is a problem in the bass and swinging two diaphragms can overcome that without the issues of simply using heavyer film (mostly sensativity loss issue)
BTW also heard here some talk here about big flat panels and their beaming will not be able to image as well as a curved panel or multiple narrow sections. Simply not true. I have built dozens of curved, multi segment, and large beamy flat panel designs and the big beamy flat panel always outperformed the others in image. Always. BUT of course the head in a vice thing that goes with this is a deal breaker for most.
You can go low with tensioned film diaphragms BUT you will need a big one so that firm tension doesnt result in a high Fs. IMO a bunch of small maybe 7 inch low mass cones run open baffle is better way to do it if only going to around 400 hz or less
Mass matters and I noticed on the super light weight protos ( 3 micron mylar and 4 micron foil) the bass just did not have the authority and power of the higher mass units (usually 12 micron mylar and 18-30 micron foils). I mention this because some here have mentioned the double diaphragmed stats bass being great. I was talking with the designer of the "Gold Ribbon" once and he said the best bass hes heard was the double diaphragmed stats. He said the issue was mass mostly. Said when the diaphragm is this light the weight of the air mass is a problem in the bass and swinging two diaphragms can overcome that without the issues of simply using heavyer film (mostly sensativity loss issue)
BTW also heard here some talk here about big flat panels and their beaming will not be able to image as well as a curved panel or multiple narrow sections. Simply not true. I have built dozens of curved, multi segment, and large beamy flat panel designs and the big beamy flat panel always outperformed the others in image. Always. BUT of course the head in a vice thing that goes with this is a deal breaker for most.
well, pretty elaborate post about building a low frequency device. I’ve got Maggie 1.7i’s I tried multiple subs first or not fast enough most of them anyway second because the recordings of the music I listen to are so varied. That one recording of the base component that’s crossed over to the sub which I do at 45 Hz never really was as fast as the Maggie’s
I ended up landing on the Martin Logan dynamo 800 X, partly because it has an app that you map your room and placement of the sub. It does a frequency sweep. On an app it then programs the sub. For your room. I use a blue sound dac that has a sub output. I can adjust it the crossover point of what it sends to the sub via the Martin Logan app I can adjust the output of the sub, overall volume. 20 to 40 Hz phase on the fly as I’m listening to the music.
So overall the Martin Logan dynamo series 600x and above that includes the app for free. I wouldn’t call him as fast as an as the Maggie but pretty close. You can have them bottom fire or by moving the feet have them front fire. I think they’re the most adjustable.
Because recordings very so much the the engineer, adjust settings I believe or the recording even at Hi-Rez very a lot. I find the Maggie can replicate very accurately pretty much any recording anomalies I find the Martin Logan after going through three or four other brands to be the fastest most adjustable on the market and a rather good price point. Of course it depends upon your other systems. Here’s mine.
I ended up landing on the Martin Logan dynamo 800 X, partly because it has an app that you map your room and placement of the sub. It does a frequency sweep. On an app it then programs the sub. For your room. I use a blue sound dac that has a sub output. I can adjust it the crossover point of what it sends to the sub via the Martin Logan app I can adjust the output of the sub, overall volume. 20 to 40 Hz phase on the fly as I’m listening to the music.
So overall the Martin Logan dynamo series 600x and above that includes the app for free. I wouldn’t call him as fast as an as the Maggie but pretty close. You can have them bottom fire or by moving the feet have them front fire. I think they’re the most adjustable.
Because recordings very so much the the engineer, adjust settings I believe or the recording even at Hi-Rez very a lot. I find the Maggie can replicate very accurately pretty much any recording anomalies I find the Martin Logan after going through three or four other brands to be the fastest most adjustable on the market and a rather good price point. Of course it depends upon your other systems. Here’s mine.
Attachments
I have a newbie question, hopefully some can guide me a bit. I made my fist pair of planar two way speakers and I love them. That being said they need a small woofer for my setup. The issue I’m have is the woofers over powering the planar. What can I do to lower it. An advice would greatly appreciated
Not necessarily. Sound Lab ESL panels here are effective down to 28-30Hz. Below that a pair of REL subs can reproduce down to 14Hz or so. Loud, low frequency bass drums come through with very good fidelity. The Sound Labs of recent are not exactly like other ESL speakers people may have heard.
A brief description by a fellow forum member who visited here a couple of times:
When I was there, Mark's speakers were one of the Soundlab behemoths, probably the Majestic series, which is a large electrostat. There were subs for the very bottom end. This was powered by high power amps. Front end was one of the DACs Mark was probably experimenting with. Vinyl was the new SP-10 Mk3 with a laser cartridge (?) plus a custom preamp for the cartridge. My speakers are a two-way, 15 inch pro woofer plus large horn mated to a compression driver.
...
The first thing I noticed was that the electrostats could play loud with little to no distortion. Much more so than my horn speakers, which can go plenty loud. I had heard electrostats before and was always disappointed that I couldn't turn it up without hitting the limit. On these, the limit is high enough that you can enjoy realistic sound levels and stunningly low distortion
...
And of course all the other stuff, such as natural timbres and textures of instruments and voices was there.
https://www.diyaudio.com/community/threads/dac-recommendation.376015/post-7560022
