Why aren't ESLs dynamic?

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I have DIY hybrid ESLs and I don't find them lacking in dynamics at all. In fact; everyone who's heard them cranked up can't believe they can play so loud with no hint of strain or distortion.

I can easily imagine full range ESLs lacking dynamics but a properly designed hybrid panel can crank out painful volume.

ESL.JPG
Hi Charlie

I am going to start playing with Ripple and just wondering if you every tried, or tried and rejected, trying to get your panels to play down to where your Ripoles are assisting?

Cheers
Grant
 
The Dayton-Wrights were designed to also work in movie theatres. The panels lock together with splines. Wright thought two sets would be good. They play plenty loud and the system resonates at 60 Hz. Although 60 Hz may not strike you as impressively low, but even with no sub, the DWs sound wonderful and full-range.

They peak loud because each matching transformer weighs 41 lbs. No kidding. If you have the watts, it has the dBs.

As per the conventional meaning of "dynamic range", ESLs excel because they are "inefficient" in the sense that audio amps need to pump out a lot of volts to make them speak. (Direct drive amps are, of course, very efficient.) So the sonic "mud" baseline in your system is inaudible thus making a wider dynamic range.

B.
 
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few ideas, but am I correct ??

I would say the "impact" is often around 70 to 100 Hz and need to pressurize the room. Harder to acheive for a planar. As said, less exursion means more surface to reach the wave length level and spl in the same time windows than the reccorded event. I talk about dynamic Jan Didden correctly described. I would add the difference between the lowest and the highest spl level IN the correct time windows.



If the room allows it: the slam and impact is a part of the dynamic definition imho. I agree it's all about group delay matching in the dynamic range. If this dynamic windows is big, say 80 dB for ilustration in a short time windows -quick drums and cymbals for instance- then you will need an acurate delay group on all the frequencies. You don't want the impact at 80 Hz that will move your chest is not going as "fast" than the upper harmonics... which is often the fact with small bass reflex in the frequencies of the event (but FIR correction of it).


Highs and harmonics are important in the slam feeling because of the harmonics... the impact is not only the chest (low frequencies) but also the ears. That's why imho sealed mid-bass with low Q (< 0.7) are often choosed with ESL and many units in an array to pressure the room better and cop with the ESL speed (time delay match) .


If no compressed reccording and always if the room permitts, there is also what Pano figured out : something boosted in the slam frequency range whatever the reccordings or sometimes the speaker (look at impulse response + the bump in the frequencies area of interest of some speakers - Dunlavy ;) for instance :D.


I believe this bump is well made by transmission line because it can fall in the "impact" range while not having the group delay (uh psycho acoustic helps :)) of a 0.5 Qtc tuned sealed speaker. But people whom have habits with unpluged music are aware of how is an acurate mid- bass : fast and light (whatever the spl).


I don't know if I'm right here, but it's all about in the delay group and the efficienty to stop the driver after the transcient then the followed harmonics in the acurate delay.

If liking the slam and impact then a VOT A5 is your friend (big area helped by impedance loaded by air due to the short horn?)... notice this one is not going naturally in the low end without help (hence the slam is in the mid-bass -and the treble- not in the two first octaves).


I bet when most of people are talking about dynamic, they indeed mix up the slam freaquency area with the length of the spl windows and also with the max spl level (not here in this forum for this last) they like at the venue -which translate at the opposit in dynamic compression at home when puping up the volume-


At the end if we are talking only about mid-bass the way the impedance adaptation between the driver and the room is very well made by mid-bass horn with sealed load. Harder job for a planar, which is also is not helped with his dipole nature when the front wall is reflective, if I understand it correctly, no ? (which I maybe don't... certainly:eek:)


Am I correct ?:confused:


I have a question please what is the equivalent Qtc (of a sealed speaker) of an ESL mylar please ? ...0.5 ?
 
Hi Charlie

I am going to start playing with Ripple and just wondering if you every tried, or tried and rejected, trying to get your panels to play down to where your Ripoles are assisting?

Cheers
Grant

The effective acoustic output of my panel (or any dipole radiator) is limited by it's dipole rolloff frequency. That is; the frequency at which the opposite-phased front/back sound waves meet at the panel's edges and begin to cancel each other.

My panel's baffle-width (width of panel + frame) is at most 18". So; the roll off begins at around 733 Hz (wavelength =18"), and output falls to half-volume (6db down) at a wavelength equivalent to 4x baffle width (about 180Hz).

Now; I could (and I do) apply some EQ boost to compensate for my panel's dipole roll off, down to the crossover frequency to the woofer (230Hz). However; for an 18" baffle width; there is already a significant trade-off (much greater diaphragm excursion) just to reach 230Hz. Going lower still would require even more diaphragm excursion and the ultimate limit is reached when the diaphragm is driven into a stator. And this is the ultimate limit of how loud the panel can play.

Conversely; if the panel is crossed over to a woofer at a higher frequency; the panel can play much louder before the diaphragm reaches X-max.

If you want to play an ESL in the bass region will significant output; you would need a panel the size of a door to get there. This is why I prefer a hybrid ESL with a conventional woofer supplying the bass energy.
 
Dynamic range is not a function of the noise floor in the room but a function of the system decay. The system must decay quickly which can be measured in a spectral waterfall plot. Any resonances in the system will raise the noise floor and reduce dynamic range. Resonances can be caused by either electrical, acoustical, or mechanical shortcomings in the system. Magnetic planar and ESL both have their own challenges to mitigate resonances, and sometimes the designers can go overboard attempting to damp resonance at the cost of suppressing transient peaks, essentially a form of distortion itself (dynamic compression).
 
It looks like once again were back too the Panels high Voltage Bias....that make the ESL work...right, No Bias No sound. ESL Bias Dose not keep up with the input to the panels....you would think in a way..we would wont it to work like a tube amps output tubes....yes you set the bias to a point, But as the input increases
The bias on the panels would increase an the dynamic range would be supported …..But No...the bias can-dose go down as the input is increased....there for the panels output cant keep up with the input....an you lose the sound of Dynamics.

All one mans thinking....
 
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It looks like once again were back too the Panels high Voltage Bias....that make the ESL work...right, No Bias No sound. ESL Bias Dose not keep up with the input to the panels....you would think in a way..we would wont it to work like a tube amps output tubes....yes you set the bias to a point, But as the input increases
The bias on the panels would increase an the dynamic range would be supported …..But No...the bias can-dose go down as the input is increased....there for the panels output cant keep up with the input....an you lose the sound of Dynamics.

All one mans thinking....
tyu, is this mitigated by adding additional servo amps? I know efficiency is lower but could bias be maintained at a higher level?
 
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Dynamic range is not a function of the noise floor in the room but a function of the system decay. The system must decay quickly which can be measured in a spectral waterfall plot. Any resonances in the system will raise the noise floor and reduce dynamic range. Resonances can be caused by either electrical, acoustical, or mechanical shortcomings in the system. Magnetic planar and ESL both have their own challenges to mitigate resonances, and sometimes the designers can go overboard attempting to damp resonance at the cost of suppressing transient peaks, essentially a form of distortion itself (dynamic compression).


Waterfall should be less than 2 ms at all frequencies between the lowest and highest spl to be sure dynamic is ok on short time windows but bellow the Helmoltz frequency of the listening room where the room is rulling ?


I don't know for the ESL but I often see the dynamic speaker has pain to have a waterfall below 2 ms under 1000 Hz. Do they not respect their dynamic range (spl) in the correct decay (timing between the lowest and highest signal)?
 
could bias be maintained at a higher level?

Ultimately, bias and drive voltage are limited by the breakdown voltage of air. Either can be increased to push sensitivity up, but once you exceed breakdown voltage for the two combined, you start losing output.

Typical insulation doesn't circumvent the breakdown voltage limit, it just lets you operate more reliably at high levels.

Insulation can cause its own problems with dielectric absorption, but that's a whole separate issue.

Dayton Wright's solution was to get rid of most of the pedestrian air, but that approach is more than what the average person will consider.
 
The driver.....of the ESl panels, the audio push pull….Tube, Soild state,or Monky shin...is not the bias in 99% of the ESL Panel drivers setups i have seen.....There are some ESL were the high voltage Bias setup useing the same Audio stepup transfourmers secdary windings that drive the panels push pull... with a added diode string... to drive the High voltag bias for the panels...but i dont think this work well...it looks like to me..its still always lower-behind the Audio drive output...

I fear-know.. that we have moved Way beond My pay gread...it would have been sloved by the minne others befor me.... with biger brains.... before my small brain had ever even thought about it....


All just a ESL sound lovers O-pine
 
Waterfall should be less than 2 ms at all frequencies between the lowest and highest spl to be sure dynamic is ok on short time windows but bellow the Helmoltz frequency of the listening room where the room is rulling ?


I don't know for the ESL but I often see the dynamic speaker has pain to have a waterfall below 2 ms under 1000 Hz. Do they not respect their dynamic range (spl) in the correct decay (timing between the lowest and highest signal)?

Certain measurement software is able to change the axis in the cumulative spectral decay plot to be periods instead of time. So the units of milliseconds changes to periods (aka cycles) which more truly represents the decay performance relative to the actual frequency of concern. This also allows a target performance to be established such as this....
The initial burst should decay by -25dB by one period. So essentially your targeted a dynamic range of 25dB across the frequency spectrum. The picture I’ve shown below is the burst decay plot for the TAD TD-2001 compression driver which is the best performing I’ve ever measured. The other is the burst decay of the BG Neo8 planar transducer.
 

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Thank you Joseph Crowe...

I'm curious about distributed little woofer panels high bass to midbass reenforcment (as the lttle magneplanars for instance but OT here or what Charlie M did in the low end with dipole dynamic speaker)...
Hybrid esl and dsp seems the easiest way to acheive dynamic... saw Martin logan increased the XO cutoff of their ESL around 500 Hz... Measurement seems not that easy indeed.
 
Thank you Joseph Crowe...

I'm curious about distributed little woofer panels high bass to midbass reenforcment (as the lttle magneplanars for instance but OT here or what Charlie M did in the low end with dipole dynamic speaker)...
Hybrid esl and dsp seems the easiest way to acheive dynamic... saw Martin logan increased the XO cutoff of their ESL around 500 Hz... Measurement seems not that easy indeed.

If your intent on improving the dynamic range with the goal of reproducing that “live” sound then you’ll need to look at using large format front horns. I’ve done extensive testing with horn loading the BG Neo8 and Neo8S planar transducer which can provide a flat frequency response from 250Hz-20KHz. This configuration produces very good dynamic range.
 
What is max spl with the neo8 on that big horn? Can you say what it is at 4m?

I calculate that it would be 100dB SPL at 4 meters using a stereo pair of E-250 Dual Planar horns. Distortion is limited to 1%.
At 90dB distortion is around 0.3%.
 

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