Full Range Electrostatic Question

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Hi,

I arrive at a different conclusion since the most important parameter to me is audible performance. Theory works only to a point.
.....
Two hundred watt amps drive SLs quite well.

Audible performance of ESLs is the prominent parameter on a personal level only
On the technical side better performance is directly related to the panels efficiency.
And guess what ... audible and technical performance coincide. ;)
Most obvious are the differences in dynamic performance and lively 'dynamic' sound impression.
The lower the panel's inherent efficiency, the more lame and boring it sounds, the Quads beeing the prime example.
And a ESL uncapable to reproduce a fff peak realistically, or loud Rock music or Techno, etc. is imho sonically restricted.

Why should one choose for 200W that do quite well, when You can do with 20W really well? :p :D

jauu
Calvin
 
And a ESL uncapable to reproduce a fff peak realistically, or loud Rock music or Techno, etc. is imho sonically restricted.
I certainly wouldn't want a speaker uncapable of playing rock or techno.

Why should one choose for 200W that do quite well, when You can do with 20W really well?
What stat(s) are you thinking of that can be driven to "loud rock music or Techno" with a 20 watt amp? I'm all ears. :)
 
Hi,

well, mine of course :D
My small panel requires only equivalent ~20W to achieve full modulation and an SPLmax of 110dB@4m (recalculated to 1m distance and a global distribution character and assuming 3dB of heat compression for a dynamic driver, the result would be impressive 125dB).
Now that´s what I call decent dynamics :D:D
The larger panel requires ~50W to achieve the same, of course over a larger bandwidth.
The Us are 1:68 resp. 1:50 and bias voltages are lowish ~2kV.
Sonics profit from low U factors of the Audio trannies.
The low required drive and bias voltages are also very positive with regard to safety, lower risk of flashover and ageing.
All this can´t be reached with FR panels within practical dimensions, probabely not at all.
Going hybrid allows to remain compact without sacrificing all the goodies.
If done right hybrids play as homogenous as any FR and tonally more even.

jauu
Calvin
 
The larger panel requires ~50W to achieve the same, of course over a larger bandwidth.
So they're not flat to 30 hz?

Going hybrid allows to remain compact without sacrificing all the goodies.If done right hybrids play as homogenous as any FR and tonally more even.
As for me I prefer the absolute coherence of a single dipole driver. And the realism that a 7 foot tall line source can provide.

To each his own.
 
I prefer the absolute coherence of a single dipole driver. And the realism that a 7 foot tall line source can provide...............

Geeessss E.......have you ever diyed a ESL?...
I think most here would say the same as you!..if...cash ....Amps....room...was as ezey for them...justsaying.
You sound like you on the SL Site.....not a diy site.....lot of people say biger is better.....but i find less can be more some times....
 
Hi,

...what appears to be a hybrid using a monopolar woofer
Oh no mon Cher, didn´t I say: "Hybrid, done right"? ;)
This means nothing other than that the pairing of a monopolar woofer and dipolar cylindrical distributing panel doesn´t add to ´absolute coherence´.
In that I agree, You´re totally right.
Instead, You have to guarantee that the lower-mids/woofer branch shows at least +-1 octave around the x-over the same distribution character as the panel.
That´s why ML used - and I still use- the dipolar tower with their Statement2.
A hybrid built that way can fulfill the coherence requirements and does away with the inherent flaws of FRs.
Besides the coherence in time and distribution character behaviour, there´s for example also the requirement for a linear amplitude response and high SPL, which a FR always compromises on.
Also the low dampened high-Q Fs will never sound as precise and dynamic as a (alot more compact) dipolar bass tower.
Even with some resistive damping the Q remains >>1.
No one will expect highly precise bass from similar specced dynamic woofer.
But there´s no theoretical nor practical hint -let alone a proof- that a ESL woofer differs from a dynamic woofer in this regard.
The only mechanism that saves the ESL bass from desaster is its usual open baffle mountage and associated distribution character and room interaction.

What remains a real con for Hybrids, is the rather bad image in general and the fact that they cost considerably more effort and more budget in manufacturing than a FR or a Hybrid featuring a monopolar Bass.
In almost all other respects they have a higher performance potential than FRs.

So they're not flat to 30 hz?
Not the panels themselves, but the system as a whole is certainly more linear in amplitude response than a FR possibly could.
The smaller system is equalized down to (sensible) 35Hz.
It could in theory be equalized to whatever bandwidth limit one wishes for.
The bigger system -coming with a subwoofer- runs down to 50 Hz, where the sub takes over till into the infrasonic range.
The system is more compact than a 7 foot tall venetian blinds, but if pushed with 200W it´d probably blow them right off their stands :D :cheers::headshot::drink:

jauu
Calvin
 
That´s why ML used - and I still use- the dipolar tower with their Statement2.
Better, but they still didn't sound like they had uniform directivity across the spectrum to me. I'll stay with a single driver, than you very much. Once again, to each his own.

The system is more compact than a 7 foot tall venetian blinds
Do you have particularly low ceilings? My other pair, Acoustat 1+1s, are nearly eight feet tall. Which fits just fine in most every American home.
 
Hi,

would You elobarate what You mean by 'uniform directivity across the spectrum'?
No single driver performs one single, constant-over-the-whole-audio-band, distribution or directivity character.
It all depends on dimensions and boundary conditions.
And even if there were transducer capable of such a performance, where's the proof that such a behaviour would be sonically superior?
I'd rather say that each directivity character has its pros and cons only over a certain restricted frequency range.
Is a dipolar cylindrical wave as advantageous at 20Hz as it is at 2kHz?
Can it be generated anyhow within practical dimensional boundaries?
I'd rather opt for the directivity that suits best within the working range of the transducer or a certain restricted frequency range, and transiting swiftly into different characters in its neighbouring frequency ranges.
With regard to my Hybrids this means that the panel exhibits a dipolar cylindrical pattern, that begins to transit into a dipolar lobed pattern at the lower bandwidth limit.
The dipolar woofer tower begins with a dipolar cylindical pattern, that soon transits into a dipolar lobed pattern that widens up with sinking frequencies.
Towards its lower bandwith limit it transits into the well known dipolar fig.8 pattern.
The subwoofer performed a global pattern under freefield conditions.
Due to the acoustic behaviour of the listening room with regard to the associated wavelengths, there is no pattern any more, but just pressurization of the room.
So, within the frequency range where modes can develop in the room, the Panel and woofer tower perform a swift transition from a widespread dipolar lobed pattern to a narrow dipolar cylindrical pattern.
No sharp breaks in the pattern, as those would be clearly audible.
Its the same behaviour that a single FR shows.
The only difference beeing the use of two Transducers that are highly optimized for their working frequency range and as such allow for improved behaviour against a single transducer.

Coming back to dipoles and 'uniform directivity':
A dipole is unable to pressurize a room, hence there's no output at all below the lowest mode of the room.....in theory.
That we can hear and measure some output -admittedly little- busts the uniform directivity myth, as it prooves that the dipole doesn't behave fully like a dipole at lowest audio frequencies underpractical, non-freefield conditions.

jauu
Calvin
 
A bit of confusion here because different people advocating for different parameters.

It seems to me that nobody claims ESLs do super side-drum low bass or atmospheric effects like thunderstorms or railroad trains. (Minor note: my cone sub-sub is a large irregularly shaped dipole with a passband 23-45 Hz and does its job just fine on those very rare moments when call upon to play.)

But at the other hybrid end (shaking cardboard to produce LF sound), you want the magic of an ESL to cover most of the musical range where your ear is sensitive. Or maybe another way to define the range is in terms of stereo effect. I'd say you'd want to be ESL down to 120, at the highest and then mix-and-match woofers below that (I have two heterogeneously located mixed-bass woofers). Of course, we've all heard great systems with just ESL tweeters or highish crossovers... but more range is even better. I suppose it is challenging (esp for commercial systems) to push the ESL range down that low.

I wish EStat could provide the more conventional loudness plot used frequently at DIYaudio like REW, 1/12 smoothing. THAT would clarify what his high-end system is doing much better than the data he posted. All it takes is a Radio Shack SPL meter and free/sharware REW software.

Yes, this is a DIY forum, but that includes sophisticated folks like EStat who are deep into system building.

Ben
 
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…better performance is directly related to the panels efficiency…The lower the panel's inherent efficiency, the more lame and boring it sounds, the Quads being the prime example. And a ESL incapable to reproduce a fff peak realistically, or loud Rock music or Techno, etc. is imho sonically restricted.
I agree. For good dynamic performance from an ESL, having an extended bandwidth is not enough.
It needs to have high output capability over its full bandwidth as well. Most/all? FR ESLs do not.

Coming back to dipoles and 'uniform directivity':
A dipole is unable to pressurize a room, hence there's no output at all below the lowest mode of the room.....in theory. That we can hear and measure some output -admittedly little- busts the uniform directivity myth, as it prooves that the dipole doesn't behave fully like a dipole at lowest audio frequencies underpractical, non-freefield conditions.

Hmmmmm…this reminds me of discussions in one of the other forums concerning use of multiple subwoofers strategically placed to smooth room response. In the bottom 2 octaves we are not just listening to the speaker response, we are listening to the room response excited by our speakers. John K… provided modeling and measurement evidence to show that at low frequencies in a room, dipole subwoofers didn’t “ignore” the room as traditionally thought. Rather, they behaved like spaced monopoles exciting the room modes from different locations with different phases. Perhaps this is why the high-ish Q of the SL distributed resonance sound better than expected. Each resonance is occurring at a different location(vertical & horizontal) in the room space and exciting the various room modes in a smoother fashion.
 
Actually, I measured over three octaves because most bass non-linearity occurs there... I spent considerable time experimenting with three variables: distance to back wall, arrangement of bass traps and bass contour setting on backplate (there are four settings in 3 db increments).
Sorry, I wasn’t suggesting only the bottom 2 octaves were flat. I only mentioned the bottom 2 octaves because that is where the distributed resonances are that we were discussing. Indeed the SL A-1 has 4 setting for LF which pick different taps on the LF transformer primary, and 4 settings for MID which put different amounts of inductance in series with the LF transformer. Attachment 1 shows stator voltage response trends for the 4 LF settings . Attachment 2 shows stator voltage response trends for the 4 MID settings . You have quite a matrix of possible responses to pick from to best match your room and placement. Note that the Brilliance control was set on high for all measurements.

Another reason this design requires high bias is the diaphragms are incredibly low in mass.
Can you expound on this comment? It doesn’t make any technical sense to me.

The advantage that Acoustat and Sound Lab have over single transformer designs is a more linear and gradual impedance curve…Look at a plot of a Quad, Innersound, etc. curve at Stereophile
I’ve heard/seen this statement a few times about the dual transformer setup producing a more linear impedance, but have found no basis for it. I think the origin of the comment is that the ESL load is a capacitance whose load impedance falls with increasing frequency. So, switching to a lower step-up ratio for the higher frequencies would help level out this falling impedance. However, for frequencies in the midrange and lower, the capacitive load from the ESL is high and not really a factor. Other than the top two octaves, the impedance seen by the amplifier is mainly defined by the transformer inductance/parasitics and their interaction with any passive crossover parts. Attachments 3-5 show some impedance curves published by Stereophile for 3 full range ESLs: SL A-1, Quad 2805, and Audiostatic ES-100. They look more similar than different to me. BTW, changing the LF and MID settings on the SL interface will change the impedance. I believe the Stereophile measurement was made with LF and MID set on 0dB or -3dB. Attachment 6 shows impedance for the SL A-1 with LF and MID both set on +3dB…the impedance drops to a punishing 2 ohm in the midrange.
 

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Never measured my Acoustat III's but can say the did not have any real bass below maybe 35 to 40 hz, so no last octave. Personally with the limits of Physics coming into play I wouldn't be looking to have 20 hz from an electrostatic panel, as another factor that may show up is that good old Doppler effect if the panel is used up into the higher frequencies at higher volume. The solution is of course, lots of panel area. Good luck in the pursuit of audio nirvana.
 
I am geting old......but to get a flat 30 hz...not talking about 6-10db down...you would have to be over 50'away......thats why i have used two 12"drivers powered
boxs...some call them subs.. in the room with what ever speakers i uses....were i can bump up the if lucky 40-50hz....i have Acoustat M3s....an thay have great bottem end....but in a room 18'X24'....Clean 40-50hz flat sounds great....

good luck with 30hz in most rooms in the home..................
 
would You elobarate what You mean by 'uniform directivity across the spectrum'?
Sure. Been out of town for the week.

Dipoles do have a figure 8 response and indeed the lowest frequencies are omnidirectional in nature. What I principally refer to is the lack of using (at least) two drivers with very different patterns of directivity used. I find a pretty audible discrepancy when dynamic drivers having pretty broad dispersion are used for say the bottom four octaves and electrostatic panels with very narrow dispersion are used for the remaining six. Especially when listening to a wide range of instruments whose sound spans both. You get harmonics with a wide perspective with the harmonics getting beamed at you.

I'd rather opt for the directivity that suits best within the working range of the transducer or a certain restricted frequency range, and transiting swiftly into different characters in its neighbouring frequency ranges.
To each his own, I find hearing major differences in directivity in any of the upper octaves annoying. For me, that isn't limited to hybrid designs either. Consider any of the 70s vintage JBL speakers like the L100, L110, etc. They run a 5" midrange all the way up to 5 khz. The good news is that the dome tweeter that follows has very wide dispersion. The bad news is that the 5" piston is beaming pretty badly at the crossover frequency. The result is the image sounds like the sonic equivalent of a funhouse mirror with wide staging at bottom and top getting pinched in the middle. Unnatural sounding to these ears.

No sharp breaks in the pattern, as those would be clearly audible.
If you're crossover is around 50-80 hz, I would agree.

Coming back to dipoles and 'uniform directivity':
A dipole is unable to pressurize a room, hence there's no output at all below the lowest mode of the room.....in theory.
As for me, I am far more concerned with the actual measured in room performance of a speaker. Mine measures flat to 30 hz - which is good enough for my purposes.

That we can hear and measure some output -admittedly little- busts the uniform directivity myth, as it prooves that the dipole doesn't behave fully like a dipole at lowest audio frequencies underpractical, non-freefield conditions.
Perhaps I should clarify my point:

The Sound Lab U-1s have uniform directivity across a 90 degree arc (via the multiple facets) in the top seven or eight octaves where our ear is most sensitive to issues of coherence. I want a piano to sound like a single instrument. Not two where the lowest registers have one stage width and character and the upper part of the keyboard has a different sound.
 
Indeed the SL A-1 has 4 setting for LF which pick different taps on the LF transformer primary, and 4 settings for MID which put different amounts of inductance in series with the LF transformer.
The current backplates use a completely different low frequency transformer blended at a lower frequency with more uniform impedance.

Can you expound on this comment? It doesn’t make any technical sense to me.
Perhaps I have confused what I've heard Dr. West say, but the "motor" of his electrostats is relatively weak as compared to others due to its design. Other than the former D-W design immersed in SF6, I don't know of any other than runs as high a bias voltage.

I’ve heard/seen this statement a few times about the dual transformer setup producing a more linear impedance, but have found no basis for it.
The basis is comparing measured curves. I'm out of town and don't have access to them, but they do not look like a roller coaster. The Acoustat is actually pretty uniform, albeit very low. The Sound Lab has relatively high impedance at the bottom but gradually falls, levels out for a while then falls again at the top octave. Neither is as "spikey" in appearance.

Attachments 3-5 show some impedance curves published by Stereophile for 3 full range ESLs: SL A-1, Quad 2805, and Audiostatic ES-100.
Note that the Sound Lab measurements were from 22 years ago. The backplate design and transformers themselves have changed significantly over the past two decades. The panel design has undergone many changes as well. The most recent change was two years ago with a new bass transformer that blends at approximately 200 hz rather than 500 hz. It is far more tube amplifier friendly.

Attachment 6 shows impedance for the SL A-1 with LF and MID both set on +3dB…the impedance drops to a punishing 2 ohm in the midrange.
I'm not sure why anyone would choose either setting. I've never run midrange at anything other than flat and find that the most linear response at the bottom in my room typically comes with the bass control at -3.
 
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snip
What I principally refer to is the lack of using (at least) two drivers with very different patterns of directivity used. I find a pretty audible discrepancy when dynamic drivers having pretty broad dispersion are used for say the bottom four octaves and electrostatic panels with very narrow dispersion are used for the remaining six. Especially when listening to a wide range of instruments whose sound spans both. You get harmonics with a wide perspective with the harmonics getting beamed at you.
snip

I think this remark, however cogent sounding it may seem, merits further clarification. "Beaming" doesn't have an audible character except second-order in terms of room ambience.

It is true that you can measure beaming, you can equalize a variably beaming system for your music chair, and you can explore beaming in your music room by moving your listening chair around. But you can't hear beaming.... or am I missing something that EStat hears?

Ben
 
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Hi,

What I principally refer to is the lack of using (at least) two drivers with very different patterns of directivity used. I find a pretty audible discrepancy when dynamic drivers having pretty broad dispersion are used for say the bottom four octaves and electrostatic panels with very narrow dispersion are used for the remaining six.
That is generally correct.
It holds true for any transducer principle.
Its only a matter of driver dimensions in relationship to wavelengths and no question of dynamic speaker or ESL at all.

If you're crossover is around 50-80 hz, I would agree.
No, this applies over the whole audible bandwidth.
Constant directivity is not needed and can't be achieved fully in praxis.
What's important is that the shape of the directivity pattern remains smooth, without sharp breaks over the frequency band.

The Sound Lab U-1s have uniform directivity across a 90 degree arc (via the multiple facets) in the top seven or eight octaves ...
Ah yes, Santa brings loot and the stork the children :D
MartinLogan claims the same BS about constant directivity with their 30° Curvelinear source. :rolleyes:
Again, it is just a matter of dimensions of the transducer against wavelengths.
If You don't believe it, believe in maths .... and read Baxandall.

jauu
Calvin
 
I think this remark, however cogent sounding it may seem, merits further clarification. "Beaming" doesn't have an audible character except second-order in terms of room ambience...But you can't hear beaming.... or am I missing something that EStat hears?
When it is consistent and frequency invariable, I would agree. I would place my Acoustat 1+1s in that category. So long as you're on axis, you get a realistic image. They beam consistently. Just don't move your head. Or expect to have a good listening area for more than one.

When part of the frequency range beams, however, and the rest doesn't, I can certainly hear the difference. Now you've got fun house mirror time in terms of the apparent soundstage.
 
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