Electrostatic speakers?

[AdamG]

“You will have to take my Electrostatic Speakers from my cold dead hands” as heard by my wife as she discussed payment plans with the local Funeral Director!

 

[misterdog]

Though if electronic instruments are your thing, then you are listening to your musiciancs choice of amps and speakers (non planar).

So his/her choice is what you are comparing your 'perfect' sound to.

How does an elctric guitar sound or an electric bass ???????????????????????????????????????????????????????????????????????????????????????

No one knows.

They only think they know from the amps and speakers they have heard them played through.


Well buy those amps and speakers then, and the recording room or studio or theatre that you have heard them in ...

 

[Blumlein 88]

Listen to acoustically played instruments by standing 'next' to them.

Then listen to your favourite loudspeaker replaying the same same recording.

Which sounds better to you, a box full of magnets and crossover or a planar dipole ?

Simple.

End.

Of.

Argument.

In my experience this procedure you described will end the argument and never have I heard the box come close.

And it was the subjective speed that was most outstanding after the lack of a box sound. Listening to acoustic guitar it sounded like the ESL managed to get about 90% of the pluck of each string. Just barely blunting the leading edge. Even excellent box speakers sound like the plucked string has been reproduced so slow about half of it was missed by the cone and domes. Like it was over before the cones speaker can even get going.

 

[Bwmr]

Ah, I am so glad to read so many of you, "hardened" scientists, in this forum, recognize that "fast" characteristics of ESL. So it seems like it's not just an illusion from the look of the transparent panels. I hear that "fast" sound even in box ESL, not just open dipole.
Any agreement on how that "fast" sound can be measured?

 

[Jazzman53]

There have been some interesting and varied views posted in this thread about the damping effect on an ESL diaphragm by its coupling to the surrounding air.

Endeavoring to keep an open mind and gain some clarity on the subject; I submitted a post about it on the DIY Audio Forum. I’ve gotten one response so far, from a well-known ESL guru and PHD physicist in New Zealand whom I respect greatly, and he has a gift for explaining complicated physics in a simple way.

I’m still pondering the response but it’s already caused me to view the question in a different way. For me; the response blew right past who’s right or wrong, to whether the right question was asked.

Below is a link to my post and response on the DIY Audio forum—draw your own conclusions.

https://www.diyaudio.com/forums/pla...mping-effect-surrounding-air.html#post6759016

 

[Blumlein 88]

There have been some interesting and varied views posted in this thread about the damping effect on an ESL diaphragm by its coupling to the surrounding air.

Endeavoring to keep an open mind and gain some clarity on the subject; I submitted a post about it on the DIY Audio Forum. I’ve gotten one response so far, from a well-known ESL guru and PHD physicist in New Zealand whom I respect greatly.

I’m still pondering the response but it’s already caused me to view the question in a different way. For me; the response blew right past who’s right or wrong, to whether the right question was asked.

Below is a link to my post and response on the DIY Audio forum—draw your own conclusions.

https://www.diyaudio.com/forums/pla...mping-effect-surrounding-air.html#post6759016

In general this is going to be how it works. Same is true of cone speakers. If you look into some books on speakers they have this all worked out. I think they cover all that in Martin Colloms book on High Performance speakers.

 

[Jazzman53]

Ah, I am so glad to read so many of you, "hardened" scientists, in this forum, recognize that "fast" characteristics of ESL. So it seems like it's not just an illusion from the look of the transparent panels. I hear that "fast" sound even in box ESL, not just open dipole.
Any agreement on how that "fast" sound can be measured?

I've seen graphs of an ESL response to a square wave input... pretty impressive.

 

[Blumlein 88]

I've seen graphs of an ESL response to a square wave input... pretty impressive.

That was a quality check with Quad ESL-63's. Had a reference model, and each one made was paired across from it with a measuring mic in between. I think they used a 1 khz square wave which those speakers could do a good job of at a distance of 1.5 meters.

To be fair a few multi-way box speakers can do that over a limited area. Thiele's all could, Vandersteens, and I seem recall Spica's could do the trick. The first two used first order crossovers. The Spica had a combined 1st and 4th order crossover.

 

[Newman]

Yes but a square wave is the wrong test. It's more of a showroom gimmick to land the sale than anything relevant to sound quality.

 

[Blumlein 88]

Yes but a square wave is the wrong test. It's more of a showroom gimmick to land the sale than anything relevant to sound quality.

Yeah, and????????????? Good stuff can't show off every so often?

 

[Raindog123]

et's try a revamped question:

Does an ES speaker permit quicker acceleration of an entire wavefront than a cone driver?

I have to say there is something that seems subjectively different about them, and the term "fast" does come to mind.

I also note that these types of questions are in the realm of attribution science.

It would be yet another of my (physics education backed) 'speculation', so would ask true experts to chip in...

The main difference might be not in how the ESL membrane vs speaker's cone interact with the air, but rather in the higher efficiency of electric signal moving the diaphragms: As a coil generates only a relatively low magnetic field, it takes high [AC] current swings to produce the sufficient force for desired SPL. Meanwhile, an electrostatic membrane (and a magnetic planar configuration) is much more current-efficient, thus can accelerate and create higher SPL's with much lower currents. Leading to lower non-linearities and - now due to a large diaphragm size - all those nice properties of better directivity.

Just a thought...

 

[Sir Sanders Zingmore]

Not sure if this directly addresses the “resonance” question but this is what Roger Sanders has said (in an email exchange regarding his speakers)

There are two important factors that the crossover frequency and its slope affects. The first and most critical involves the electrostatic panel's fundamental resonance. To make a long story short, it is essential that you do NOT operate the panels at their fundamental resonance. Doing so causes high Q bass, which sounds boomy and muddy -- just the opposite of the rest of an ESL's range that is very low Q and therefore very clean and detailed.
>>
>> Operating the panel at its fundamental resonance also ruins the panel's linear frequency response as the resonance introduces about a 16 dB peak at the resonance frequency (which lies somewhere in the 80 Hz range depending on atmospheric factors). Not only does this massive resonance ruin the frequency response, but it also causes enormous diaphragm excursion, which dramatically limits the output of the panel, thereby making it impossible to play dynamic music loudly.
>>
>> What all this means is that it is essential that the crossover severely suppresses the electrical signal in the region of the fundamental resonance. In practice, the signal at the fundamental resonance should be reduced by at least 50 dB relative to the reference level. By using 48 dB/octave slopes, this can be accomplished in just one octave, which makes it possible to use the very low crossover point of 170 Hz.​

 

[Wes]

It would be yet another of my (physics education backed) 'speculation', so would ask true experts to chip in...

The main difference might be not in how the ESL membrane vs speaker's cone interact with the air, but rather in the higher efficiency of electric signal moving the diaphragms: As a coil generates only a relatively low magnetic field, it takes high [AC] current swings to produce the sufficient force for desired SPL. Meanwhile, an electrostatic membrane (and a magnetic planar configuration) is much more current-efficient, thus can accelerate and create higher SPL's with much lower currents. Leading to lower non-linearities and - now due to a large diaphragm size - all those nice properties of better directivity.

Just a thought...

Seems like a good thought. My Maggies certainly seem "fast" - it could be just wavefront launch

I am looking forward to seeing if Magnepan can produce an affordable speaker that takes up less space...

 

[egellings]

You do have to swing higher current in a voice coil, but you get to do that at lower voltages. You do get to swing a lower current in an ESL, but you have to swing higher voltages. It's a tradeoff however you do it. Of course, with the lower voltages required for voice coils, that makes them the preferred choice for electronics, since lower voltages with higher currents are easier to achieve without the use of direct-coupled vacuum tubes or step up xfmrs.

 

[Newman]

There have been some interesting and varied views posted in this thread about the damping effect on an ESL diaphragm by its coupling to the surrounding air.

First of all, I didn't post "views", I posted a calculation, and it wasn't about damping, it was about the mass of the diaphragm compared to that of the air it moves. Regarding damping, I specifically said I am not commenting on whether it rings or not.

Endeavoring to keep an open mind and gain some clarity on the subject; I submitted a post about it on the DIY Audio Forum. I’ve gotten one response so far, from a well-known ESL guru and PHD physicist in New Zealand whom I respect greatly, and he has a gift for explaining complicated physics in a simple way.

I’m still pondering the response but it’s already caused me to view the question in a different way. For me; the response blew right past who’s right or wrong, to whether the right question was asked.

Below is a link to my post and response on the DIY Audio forum—draw your own conclusions.

https://www.diyaudio.com/forums/pla...mping-effect-surrounding-air.html#post6759016

Nothing wrong with Rod's comments, but doesn't change the fact that it is wrong of you to refer to the diaphragm as much lighter than the air it moves.

What really happens is that as the frequency rises, the acceleration of the membrane rises, hence the volume of air being displaced resists more (F=ma, and we just increased a). And, at low frequencies, where the stat panel's drumhead resonances lie and damping would be most helpful, the acceleration is lowest and the air is least help with damping.

Also note how Rod describes the system as "grossly over damped" at high frequencies. This means that stat panels have a slow response to fast signals.

© WTWH Media LLC

It doesn't matter in practice -- real music allows plenty of build-up time for over-damped transducers to build up their response -- but please, let's put to bed this myth that stat panels have some kind of natural advantage in 'speed' with transients. The opposite is true: many conventional tweeters have the advantage in agility, by not being "grossly over damped".

cheers

 

[ferrellms]

I see no discussion about them around here, are they that bad? Martin Logans look pretty cool.

I had Acoustats for a while. They could sound just amazing or not so good depending on the material and where your head was. Very beamy all the time and big but messy and unstable imaging, various colorations that were hard to figure out, not much volume handling - BUT with the right recording and your ears in just the right place - wow! Dumped them and went back to my LS35As. Overall, the little guys were more listenable and less colored, and thus preferable, but without the occasional goosebumps of the big flatties. My current Genelecs are superior to either, IMHO.

 

[Harmonie]

I just found a new old one

Sony ...

 

[bolserst]

…An ESL diaphragm isn't lighter than air of course but it's significantly lighter than the mass of air it's coupled to and moves. In this respect physics favors lower mass.

Let’s test this claim.

Stator gap 0.063 in = 1.6 mm
Density of air = 1.22 kg/m3
mass of 3.5µm Mylar = 5 g/m2
Maximum mass of air being moved (1.6 mm of diaphragm movement at the point of arcing) = 1.22x1000x0.0016 = 2 g/m2
At typical diaphragm movements, eg 1/10th of the full gap for much of the time, the air being moved is 0.2 g/m2, which is 1/25th of the mass of the diaphragm.
Your claim doesn’t hold up. In fact, the ESL diaphragm is significantly heavier than the mass of air it's coupled to and moves.

I think Jazzman53’s comment is phrased correctly. (ie the ESL diaphragm is significantly lighter than the mass of air it is coupled to)

Based on comments you made in Post # 495 I gather you are familiar with the radiation impedance curves for pistons in infinite baffles or in free air(ie dipole) Note that they are normalized, so the factor of 1 you mentioned needs to be multiplied by the normalization factor to determine the mechanical impedance the transducer motor is trying to move.

Revisiting your example and using a 1m^2 ESL (similar to a Quad ESL63), the mass of air coupled to the diaphragm(ie radiation impedance) can be calculated using radiation impedance curves published by Tim Mellow for membranes: https://www.frontro.co.uk/publications
They are similar in magnitude to those for rigid piston curves I attached, but missing most of the diffraction related ripples.

Plotting mechanical impedance on a log-log plot is nice because mass or stiffness show up as straight lines. This makes it easy to see that the radiation reactance is 1050g and significantly larger(~200x) than the diaphragm mass of 4.8g. If the diaphragm tension was adjusted to give a resonance of 40Hz in air, it would be about 600Hz in a vacuum. Notice also that above 1kHz the mechanical impedance is predominately resistive until you approach the HF roll-off point were the reactance of the diaphragm mass surpasses the radiation resistance. Of course the radiation impedance will change for different size/shaped diaphragms, but this example is typical of what you will find with all ESLs.

Creating a similar plot for a recent Satori Beryllium dome tweeter, you can see that the mass of the voice coil and dome dominate the mechanical impedance driven by the motor.

 

[Newman]

A wee bit over-semantic IMHO.

The unit of acoustic impedance is not grams. Attempting to re-configure it as a kind of grams-equivalent is a case of try-too-hard. Like describing electrical impedance in amp-equivalents.

Let's stick to talking about the actual mass of the actual air that is physically displaced by the movement of the panel. That, after all, is the statement I took issue with: "the mass of air it is coupled to and moves".

(P.S. it is obvious that jazzman doesn't know the stuff he attempted to lecture us about (he says so himself the moment he is challenged), and when taken to task over a mis-statement, he has gone running to his diyaudio guru pals and either quoted here Rod's response there (which I have already agreed with) or, in this case, got you to register here, Steve, specifically to argue the case. If you had shown me that the actual mass of the air that is actually displaced by the panel (even allowing a little more for the air displaced by the displaced air) was "200x" greater than the panel mass, instead of re-configuring the actual units of acoustic impedance to a gram-equivalent, it would have been both interesting and amazing, but of course you didn't and it isn't. After all, I never said the acceleration-dependent impedance of the air doesn't create an acoustic reaction, but that is also not what jazzman said in the first place. He was too loose with words, I took him to task over it, and now we are pretending he said something completely different and which would have been correct, if only he had said it. Utterly pointless and IMO a cheap debating tactic. I am not in a debate about the acoustics of ESLs, so let's not pretend I am. All this back-and-forth over multiple forums, rather than just say "oops I was too loose with words, I actually meant to talk about acoustic impedance", and it would have been over before it started. But no.)

 

[Martini]

Hey gang, I picked up a set of Revel F328Be and now my pair of Martin Logan Aerius-i available. They are in very nice condition, covered when I wasn't listening and never in direct sunlight. Right after the pandemic started I replaced the cheap binding post, because they had started spinning. I replaced them with SpeakOn connectors. All capacitors in the crossover looked good, with no bulging or leaking. Honestly, I'd like to keep them to use with the TV in our living room, but someone doesn't want them in there , so I guess they got to go. I'm not sure what to ask for these, because I know shipping those big boxes won't be cheap. If you're interested, make a reasonable offer or if not interest maybe shoot me some guidance on what to ask when I post them.