What do panels sound like when overdriven?

[Webinattor]

I have never heard my speakers distort before in the 8 years I've run them. Probably because I have never overdriven them. However, I just added an outboard amplifer to my setup and am tempted to crank it up more than in the past.

What would I need to listen for if I am over driving them? I could tell with cone speakers because they'd start to pop and bottom out etc.

Where is the point of "over excursion" on an electrostatic and what does that
sound like? Or do they just "fry."

 

[tonepub]

I've yet to overdrive the Summits, even with 350 wpc on tap.

However, when I had my CLS's and Aerius's, if I crept up on it slowly,
I could usually hear the soundstage collapse first. Then, if I pushed further
I could hear the panels rattle a bit.

 

[Webinattor]

Ok, thanks. I'll watch out for rattling. I'm pushing them hard today and don't want to hurt the speaker. Thks.

 

[Craig]

The panels can take a lot of power and are capable of playing very loud. You'll probably hear the amp start to clip or the cone woofers blowing out before anything happens to the electrostat panels if you can stand it that loud. The CLS line are the only MLs that are not a hybrid speaker and it takes plenty of power to drive them so it would take a powerful amp to test their limits. And when you reach the high volume distortion levels how will you know if it is the amp entering the distortion zone or the speaker? I'm sure there is a limit but I don't know of anyone willing to sacrifice their panels to find out what that limit is.

 

[JonFo]

Modern ESL panels from ML are near indestructible.

The upstream components, like the audio step up transformer or crossover elements will likely blow before the panel is damaged.

If (and that's a big IF) you got enough current to the stators, you might get diaphragm slap agaisnt the stators, but that's about it.

 

[JohnA]

Interesting question, I've been wondering about this myself.

Have played them very-very loud (RatShack digital meter off the scale) and it was surprising how composed they remain.

 

[C.A.P]

I have driven my old Quest. as hard as I could. They never distorted or slaped. That being said........they only had to drop to one hundred fifty hz and then the woofer augmented them. Now the woofers would start to fall apart and muddy up things after that but its common knowledge that even the best woofers are hard to blend with the dynamics of the panel.

The CLS is a diferent beast all together. It produces usable bass down to forty hz. It is down a few db but it is there. As the bass goes deeper it starts to naturally roll off and drop in db. That is why blending a sub is so easy. you don't have a crossover to deal with and a phase timing of a panel and woofer . If your panels are older or the Mylar is stretched you can get some kazoo buzz happening at higher volumes. This usually can be treated with the hair dryer. Martin Logan panels are a tough panel that is VERY simple in design yet very efficient at their job.
If you do not have a very high current amp.......Krell.....Pass.....Big Macs.....you will likely get distortion much faster when turning the volume up. I have had people coment on how loud and CLEAN my system sounds.

That goes back to the upstream equipment ......Garbage in.....Garbage out.

 

[DrJRapp]

I have my Summits being driven by 600 wpc and haven't yet heard their limits...and I've played them very loud.

I believe your first audible indication may be the character of the sound itself. It will problably start to seem more compressed and less open before you get any other artifacts.

 

[VanDaRo]

Panel distortion sounds completely different than cone-driver distortion. It manifests itself as a collapse of intensity first, then sound stage wipe-out. It is not harsh or agony-inducing like dynamic speakers, but still clearly audible.

If you hear it, turn it down.

BTW... The high voltage interface will shut down well before you damage the panel. Whether this is a thermal overload or a current level trip is unclear to me as I have never studied the available schematics. But if you blast the speakers too hard, one or both will shut down for about five minutes before you can restart them.

Yes, I have done this whilst in a drunken stupor.....

~VDR

 

[Gordon]

Where do we draw the line to define a low/high current amp? Is 100 amps considered low current?

Gordon

 

[JohnA]

Where do we draw the line to define a low/high current amp? Is 100 amps considered low current?

Gordon

Ah, but what exactly does this '100 amps' really mean?
is it a theoretical maximum delivered by the powersupply on a single channel for half a millisecond with 50%THD, or is it a maximum value that can be measured at the speaker terminals?
(I can't think of many speakers that could take this sort of punishment for one, the coils would glow red)

 

[JonFo]

...

BTW... The high voltage interface will shut down well before you damage the panel. Whether this is a thermal overload or a current level trip is unclear to me as I have never studied the available schematics. But if you blast the speakers too hard, one or both will shut down for about five minutes before you can restart them.
...
~VDR

Depends on the model, but none of the schematics I've studied, nor the units I've worked on have any kind of protection for the Panel.

Not that any is needed. As i said, ESL's are pretty stout. There is nothing to 'damage' except if there is arcing. and with ML's powder-coated stators, there should be perfect electrical isolation, so even if the diaphragm is laying up against the stator during a 'slap', there should be no arcing, and therefore, no damage.

But the amount of current necessary to do that is likely to melt the step-up transformer input windings. So there is some protection

As for how much current they can take, I'd estimate most can handle 100amps for a few milliseconds, and the bigger units (CLS/Monolith/Quest/Prodigy) can take a few more milliseconds than the smaller panels. But >1 sec would surely burn out the transformer on any unit.

So at small duty cycles, (appropriate to high-frequencies, which is where the largest draw is), they should be able to absorb a good bit of current.

This is why amps that are current limited distort and don't sound good on ML's.

 

[VanDaRo]

I should clarify -- When you give the speaker(s) too much juice, something in the interface shuts down the entire speaker, not just the ESL panel.

Nevertheless, the sound remains a dead giveaway should you drive them too hard.

~VDR

 

[Webinattor]

I spent a great deal of my 4th doing critical listening and "cranking" my system with my new amplifier (Emotiva). Happily, I didn't break anything
but did push my setup quite a bit. (to the point of sound stage collapse etc.)

Although I spent a good deal of time doing speaker setup years ago,...exact measurements from walls and such... I was again reminded of how absolutely picky and merciless ML's are with their setup since I messed with that again over the weekend.

I can't keep tweeking that aspect and it looks like I have another weekend or so to do of that. :rocker:

 

[Horchem1972]

The soundstage collapse is probably your amplifier.

:rocker:The soundstage collapsing was probably due to the amplifier.I would say that 99% of the time the woofer will reach its limit before the panels.The panels first only if there is a loose section that rattles.High current amps are usually stated as amps that double their power as the impedance halves.A popular example is the Sunfire,which is 200watts @ 8ohms and 400 @ 4ohms.What speakers are you using?I am sorry if I missed the model.There is a huge differance between clean undistorted wattage and distortion wattage.

 

[VanDaRo]

Not a chance...

Well if you were speaking to my comment on "soundstage collapse":

No disrespect intended Horchem, but there is almost no way that my amps give up before the speakers. The Logans are vertically bi-amped by the pair of Acurus A-150s, which are rated to deliver 150 Wpc into 8 Ohms at <0.06% THD. They were grossly underrated by the manufacturer. In fact, The Absolute Sound measured them at 220 Wpc and 325 Wpc into 4 Ohms at the rated distortion levels. Given that the speakers each have a dedicated amp, one could figure that there is 440/650 Watts available to each speaker at 8/4 Ohms.

Okay, so the amplifiers aren't perfect voltage sources. But they definately have the required horsepower and torque to crunch almost any speaker on the market today... and that would include the Sequel IIs.

I firmly stand by my statements above. Once the diaphragms start to slap the stators, things go bad. Push it further and the speaker will quit.

I cannot stress strongly enough that this is a cruel and unusual thing to do to a nice pair of speakers... but it happens occasionally if you and your friends have to much Captain Morgan's and The Rippingtons are sounding really good...

~VDR

 

[Horchem1972]

I was referring to webinnator post.

It is common when many amplifiers are being pushed too hard that the soundstage collapses just before the clipping point.Even though an amplifier puts out 300 watts at 4-ohm does not mean it will power ESL panels effectively.It is current and not wattage that counts.Many companies will not test their amps below 4 ohms because they will show low output or blow fuses.A 300 watt amp at 4-ohms may only put out 50 watts at 1-ohm.You must remember that an ESL panel will routinely dip down to 1-ohm.This presents a load that most amplifers cannot handle effectively.I have never heard a proper functioning panel give out before the woofers on Logans,with their crossover point.The panels usually bottoms out due to a loose secton in the panels or being driven by distortion.This is only my experience and others may differ.If you are really curious,try e-mailing Jim Power at ML.I am sure he probably has his own opinions.:music: