[Rocket_Ronny]

"One problem I hear in all electrostats--- dynamic compression. The explosive quality of drum rimshot or the "edge" on a trumpet is not there like a ribbon speaker. I am not the only one that finds that lacking

Well said and I agree. There is a liveliness with ribbons I am drawn to.


Rocket_Ronny

[studiotech]

Interesting that you mention that, because Wendell was asking about it yesterday. He says, "One problem I hear in all electrostats--- dynamic compression. The explosive quality of drum rimshot or the "edge" on a trumpet is not there like a ribbon speaker. I am not the only one that finds that lacking, but it is seldom mentioned when comparing the pros and cons." And he was wondering whether that was due to the transformer, or something else.

Well, my Raal uses a transformer and it never sounds dynamically compressed when used high enough in range.  I think I was not clear above in my other statement.  I did not mean to suggest that ribbons were dynamically limited as the smaller planars tend to be, only that they seem to get leading egde of transients correct as well.  Funny that Wendell notices it about stats but not any Maggies?  In my experience they act the same dynamically.

I do agree though that even some of the larger Stats I've heard seem to squash transients max level.  It's an odd sensation though because as I mentioned they get the stop and start of the transient so right, but not the peak I guess.  I wonder if the strength of the electrostatic field drops off more rapidly than that of magnets so with additional excursion, they loose full force acting on the diaphragm?  That doesn't seem right though since they are acting as a push pull device, so I got nothing other than what I hear.

Greg

[studiotech]

I may love my planars but here's one aspect of it that I really hate:

Bell Laboratory’s electrostat was something to behold. This enormous bipolar speaker was as big as a door. The diaphragm, which was beginning to rot, was made of a pig intestine that was covered with fine gold leaf to conduct the audio signal.

The flies in the Summer are just beyond belief.

Hmmm, do I smell chitlins?  Oh no, that's just the finale of the 1812 Overture.  Ewwwww. 

[Rclark]

I have heard the Neo 3 driver, and an electrostat as well. What I think would be cool is if you could somehow get a planar to retain what it does so well, but also figure out a way to give it some more X-max.

[jsm71]

Well, my Raal uses a transformer and it never sounds dynamically compressed when used high enough in range.  I think I was not clear above in my other statement.  I did not mean to suggest that ribbons were dynamically limited as the smaller planars tend to be, only that they seem to get leading egde of transients correct as well.  Funny that Wendell notices it about stats but not any Maggies?  In my experience they act the same dynamically.

I do agree though that even some of the larger Stats I've heard seem to squash transients max level.  It's an odd sensation though because as I mentioned they get the stop and start of the transient so right, but not the peak I guess.  I wonder if the strength of the electrostatic field drops off more rapidly than that of magnets so with additional excursion, they loose full force acting on the diaphragm?  That doesn't seem right though since they are acting as a push pull device, so I got nothing other than what I hear.

Greg

The issue with transients and planars (not just stats) is because of the dipole implementation.  David Janszen (zA2.1 model) and Harold Beveridge (Model 2) are two designers (not sure if there are more) who understand this and design electrostatic speakers using a monopole approach.

I don't fully understand it all as a non-engineer, but I love my JansZens.  Everything coming from the stat panels just sounds true. 

David goes into this on his web site:  "You might be familiar with see-though ESL's, but these and most other non-JansZen ESL's are similar to one another, in the sense that the membrane motion is not damped. Our membranes, however, have just the right amount of damping.

Why is that good? As with a shock absorber, all motion is ideally controlled, reacting precisely to the musical signal, never bouncing and bucking along on its own after a sound is supposed to end. This optimizes transient response and eliminates the resonant coloration and break up that affects all undamped planars.

Our ESL's keep the loud transient sounds intact, even at high average loudness, and this contributes to the sense of realism and dynamism. This is possible because our panels are insulated in a way that allows overloads that are three times as high as what will ionize the air in the gaps. Also, the matching transformers can handle these overloads without saturating and putting a low impedance across your amplifier. Lastly, there's no electronic voltage limiting that could compress the peaks.

As a result, brief, transient overloads, like from drum or piano hammer strikes, will simply be as loud as they are supposed to be, even though the speaker is technically overloaded. You are also free to use amplifiers with significant headroom without worrying about ruining the panels or damaging your amplifiers."

[*Scotty*]

Rclark, the work around for more excursion on a planer is increasing the surface area of the planer magnetic driver. This is how you get higher output with lower distortion in the bass frequencies.
As far as high SPL transients and Maggies are concerned, I think the problem is coming from the singled end drive nature of the Magneplaner. It only has a magnetic field on one side of the voice coil, and as the drive voltage increases the membrane is pushed ever further away from the point where the magnetic flux density is at its maximum. This is built in non-linearity, the driver as such does not have a linear area of operation.
 As the drive voltage is increased, as on a high level transient, the electro motive forces causing increased excursion hit a point where they are pushing against a low enough flux density that further outward motion falls off rapidly and virtually ceases.
 Compression and finally peak limiting occurs. Compression onset is gradual and even the peak limiting may not be a that noticeable. In my opinion they still do many things right.
 A well designed conventional cone type loudspeaker, on the other hand, has had a great deal of effort expended to insure that that magnetic flux density in the voice coil gap is constant. The better drivers are also so designed that the voice coil does not leave this region of constant flux density during normal operation within linear Xmax parameters.
It should be said that a cone driver's distortion also increases with excursion however it is possible that some cone drivers start with enough driver sensitivity and a low enough level of THD and IM distortion that they can exceed a maggies peak SPL output on a high level transient with lower distortion and be preferred for that reason.
Obviously, YMMV.
Scotty

[a.wayne]

Well, my Raal uses a transformer and it never sounds dynamically compressed when used high enough in range.  I think I was not clear above in my other statement.  I did not mean to suggest that ribbons were dynamically limited as the smaller planars tend to be, only that they seem to get leading egde of transients correct as well.  Funny that Wendell notices it about stats but not any Maggies?  In my experience they act the same dynamically.

I do agree though that even some of the larger Stats I've heard seem to squash transients max level.  It's an odd sensation though because as I mentioned they get the stop and start of the transient so right, but not the peak I guess.  I wonder if the strength of the electrostatic field drops off more rapidly than that of magnets so with additional excursion, they loose full force acting on the diaphragm?  That doesn't seem right though since they are acting as a push pull device, so I got nothing other than what I hear.

Greg

Hello,

Transformers are a no, no, if low distortion and sound quality is the target, when using transformers the goal is usually one of impedance control.  IMO Both ESL and Maggies,  suffers from a lack of percussive energy, something dynamic speakers have in spades, Ribbons suffer from it less than ESL ( more mass)  Apogees had it somewhat   and dynamic speaker/ribbon Hybrids suffer from it the least and is the best compromise to me ...

[jimdgoulding]

When I get around to demo-ing the Magnepan 1.7's, I'll be sure and take along Rachmaninoff's Symphonic Dances with The Dallas Symphony and DAFOS on Reference Recordings.  The former has bass drum whacks that while the notes are not all that low, the PROPULSION into the room is mind boggling on analog.  The Dafos record DOES have some really low bass information.

[*Scotty*]

The Telarc recording of Groff's Grand Canyon Suite is sure to do them in. If you have over two hundred watts on tap you can pop both mid and tweeter fuses on the 3 series on the peaks.
It's one scary piece of music. The warning label should actually be heeded on this case.
Scotty

[josh358]

Well, my Raal uses a transformer and it never sounds dynamically compressed when used high enough in range.  I think I was not clear above in my other statement.  I did not mean to suggest that ribbons were dynamically limited as the smaller planars tend to be, only that they seem to get leading egde of transients correct as well.  Funny that Wendell notices it about stats but not any Maggies?  In my experience they act the same dynamically.

I do agree though that even some of the larger Stats I've heard seem to squash transients max level.  It's an odd sensation though because as I mentioned they get the stop and start of the transient so right, but not the peak I guess.  I wonder if the strength of the electrostatic field drops off more rapidly than that of magnets so with additional excursion, they loose full force acting on the diaphragm?  That doesn't seem right though since they are acting as a push pull device, so I got nothing other than what I hear.

Greg

Exactly, the field should be pretty linear. So something else seems to be squashing the transients. There's no question that, for a given area, ribbons can produce higher amplitudes than stats. If you overdrove the stats, they would arc. But that isn't happening, so it would seem that the compression is happening ahead of the diaphragm. Transformers? My understanding is that saturation is more of a problem in the bass. If it happens at higher frequencies, though, it can sound very much like clipping. as an alternative explanation, I was wondering if the amplifiers weren't giving out. My first thought was that the impedance can drop to an ohm at 20 kHz, and as low as 0.3 ohms higher up, and that transients are rich in high frequency energy. But then it occurred to me that the problem could more plausibly be occurring further down, in the midrange, where the low frequency transformer crosses over to the high frequency transformer. You get a double impedance dip, and that can be associated with a high phase angle, as in these Martin-Logans:

Since levels are high in the midrange, you could be seeing current clipping, or the amp's protective circuitry could be kicking in because of the high phase angle. But I don't have enough data to more than speculate. Maybe someone who really knows stats knows?

EDIT -- Just read jsm71's post above, and I see he quotes David Janszen on this -- just the kind of authority I was hoping for!

[josh358]

I have heard the Neo 3 driver, and an electrostat as well. What I think would be cool is if you could somehow get a planar to retain what it does so well, but also figure out a way to give it some more X-max.

There are some designs that do that, including the Neo 10 and 8S, and even moreso, some sound reinforcement planars. You have to do is increase field strength, which can be done with Neodynium magnets. Then you can move the pole pieces further apart without reducing the Bl product. But it's expensive because of the cost of Neodynium and stronger magnet structures. Also, you start to have heat dissipation problems. In smaller planar drivers like the Neos, this is addressed with high temperature adhesives and membranes, e.g., Kapton. The big Wisdom Audios achieve high SPL's by using spun silver to draw off heat from the tweeters.

Other issues with planars include dishing of the diaphragm. It moves like a trampoline rather than a sheet. Surrounds, like in the Analysis Audio, or pleating like in the Neo 10 can improve excursion and damp of traveling waves but they add to cost.

Planar woofers actually put out enormous amounts of bass, but they have to make up for the 6 dB/octave dipole bass cancellation. To keep response flat as wavelength increases, the excursion of a planar woofer has to increase as the cube! Dynamic woofers are stressed by dipole bass as well. The DWM woofer offers one partial solution to that -- since it's positioned against the wall, the baffle acts as if it were twice as wide, pushing down the point at which the 6 dB/octave cancellation begins.

[*Scotty*]

If the transformer that steps up the signal voltage behaves like the the transformer in the output stage of a tube amplifier, then the small signal bandwidth,say 1 watt and under, could look quite respectable, however when the power levels are raised core saturation effects become noticeable below 100hz and the inter-winding capacitance starts to roll off the highs. The end result is that as the incoming signal power levels are raised the speaker becomes increasingly bandwidth limited, hysteresis distortion is present at all power levels.
 The design of the transformer that steps up the signal levels' voltage is going to be critical to maintaining the speakers bandwidth as the power level goes up.
The impedance peaks at 500Hz and 4500Hz seen in the SL3 graph are likely due to notch filters used to control panel resonances.
Scotty

[JohnR]

If you overdrove the stats, they would arc.

Hi, I don't know about all stats but at least some modern stats don't arc.

[josh358]

Hi, I don't know about all stats but at least some modern stats don't arc.

Good point. I take it that includes the Janszen's, if his description of the coating is accurate.

[josh358]

If the transformer that steps up the signal voltage behaves like the the transformer in the output stage of a tube amplifier, then the small signal bandwidth,say 1 watt and under, could look quite respectable, however when the power levels are raised core saturation effects become noticeable below 100hz and the inter-winding capacitance starts to roll off the highs. The end result is that as the incoming signal power levels are raised the speaker becomes increasingly bandwidth limited, hysteresis distortion is present at all power levels.
 The design of the transformer that steps up the signal levels' voltage is going to be critical to maintaining the speakers bandwidth as the power level goes up.
The impedance peaks at 500Hz and 4500Hz seen in the SL3 graph are likely due to notch filters used to control panel resonances.
Scotty

Interesting. I wonder if that's what Wendell is hearing.

[*Scotty*]

A good tutorial on electrostatic loudspeaker principles can found at this link courtesy of SoundLab speakers.
http://www.soundlab-speakers.com/#!__technology
SoundLab uses a toroidal step up transformer for what its worth.
Scotty

[studiotech]

There are some designs that do that, including the Neo 10 and 8S, and even moreso, some sound reinforcement planars. You have to do is increase field strength, which can be done with Neodynium magnets. Then you can move the pole pieces further apart without reducing the Bl product.

Yes, yes, yes!  This is the reason I've been trying forever to get my hands on some of the MAD planar elements from their PA systems that I linked to above.  These were my holy grail before the Neo10 became available.  I'd still love to track some down to do a comparison.

I still keep coming back to a comparo with the ER driver too.  It might stand a better chance of acceptable dynamics used as wideband midrange by avoiding those ultra low and nasty, difficult to drive highs getting pushed through the transformer.

At one point I spoke with Eminent Tech and they offered to make neodymium versions of their planar mid driver for me.  Claimed sensitivity would go up by at least 6dB!  That's a whopper of a gain.  This was also before the Neo10 was DIYable.

Anyone for an uber, neo, push-pull Maggie with pleated surround and hi-tech diaphragm?  Could still cost less than Wisdom even with rather limited production.

Great thread guys.  Keep the good info coming.

Greg

[josh358]

I asked Wendell about surrounds the other day. I know it's not a new concept to them, Jim Winey has a patent on a styrofoam planar with a surround, and I'd just read something about the Analysis using a surround on its woofer. Analysis was claiming that the surround suppressed traveling waves. They also apparently use quilted foil to the same ends, and IIRC the surround are on the Neo 10 and 8S is pleated. Apparently the issue is one of cost -- the Analysis writeup said that the woofers are expensive to install. I think it would be great in a top end speaker, though.

I've also asked about Neodynium magnets and he pointed out that it's cheaper to buy a big amp than it is to buy a speaker made with neodynium magnets. Of course, that doesn't touch on the possibility of higher SPL's in a high end model.

Magnepan sees itself as a value manufacturer, and Wendell is concerned that entering the realm of ultra-expensive speakers would tarnish that image. However, they used to make the Tympani and I think there's room for a higher end speaker in their line. I mean, these days, anything under $200,000 is considered a bargain.

Meanwhile, adding the Neos to Tympanis seems to me a great way to go. Or something like the ER driver, if a line of them would produce sufficient SPL's, and you could handle the dispersion issues since it's wider than the original mids. Also, I'm always waiting for someone to make a line source electrostat using ESL-63 technology, and I've heard that someone is finally working on one. Don't know how far it will get.

[josh358]

A good tutorial on electrostatic loudspeaker principles can found at this link courtesy of SoundLab speakers.
http://www.soundlab-speakers.com/#!__technology
SoundLab uses a toroidal step up transformer for what its worth.
Scotty

I've been reading about their new transformer, and also a long thread on I think DIY audio about a transformer that someone is making to order in Canada.

[jhm731]

I asked Wendell about surrounds the other day. I know it's not a new concept to them, Jim Winey has a patent on a styrofoam planar with a surround, and I'd just read something about the Analysis using a surround on its woofer. Analysis was claiming that the surround suppressed traveling waves. They also apparently use quilted foil to the same ends, and IIRC the surround are on the Neo 10 and 8S is pleated. Apparently the issue is one of cost -- the Analysis writeup said that the woofers are expensive to install. I think it would be great in a top end speaker, though.

I've also asked about Neodynium magnets and he pointed out that it's cheaper to buy a big amp than it is to buy a speaker made with neodynium magnets. Of course, that doesn't touch on the possibility of higher SPL's in a high end model.

Magnepan sees itself as a value manufacturer, and Wendell is concerned that entering the realm of ultra-expensive speakers would tarnish that image. However, they used to make the Tympani and I think there's room for a higher end speaker in their line. I mean, these days, anything under $200,000 is considered a bargain.

Meanwhile, adding the Neos to Tympanis seems to me a great way to go. Or something like the ER driver, if a line of them would produce sufficient SPL's, and you could handle the dispersion issues since it's wider than the original mids. Also, I'm always waiting for someone to make a line source electrostat using ESL-63 technology, and I've heard that someone is finally working on one. Don't know how far it will get.

IMO, Magnepan has their head in the sand.

Audiophiles have repeatly shown that they are willing to pay for high performance products.

A big amp isn't going to give you the same effect as improving the speaker's efficiency and transient reponse.