Make it worse to make it better???

[torroid88]

Hunt, in "Electroacoustics" addresses the issue of a lack of symmetry. One of the assumptions made at the outset of his analysis of the push-pull case is symmetrical positioning of the stators relative to the central diaphragm. He goes on to show the diappearence of distortion terms due to this symmetry in his mathematical analysis... Near the end of all of this, he states that distortion remains below 1% for capacitance differences between the two halves of 8% ...

[moray james]

there are a fair number of different patents to generate the voltage for a diaphragm from the audio component. Most of these are for esl headphones but some are specific to loudspeakers. Perhaps one of those would provide a way to insert some audio into the polarizing voltage.

[Calvin]

Hi,

I haven´t read all the answers, but MJ Your assumption is wrong under the following circumstances:
1st: between the plates exists a homogenous field and
2nd: the ESL is a constant charge device
This is the way most modern ESLs are constructed.

With these premises in mind the actual position of the membrane plays no role. Keep in mind that the application of a polarizing voltage offsets the membrane from the centered position anyway.
ML works successfully with different front-to-back-stator-d/s, so do I. Imbalances of up to 25% don´t effect distortion values consioderably.

As for curved stators I can´t agree with You. My experience is that distortion is rather a matter of excursion and the transformer quality rather than curvature or flatness.
If You want distortion let the panel work with low frequency content below 150Hz and use a small cored tranny driven into saturation.

As for my panels I even couldn´t state how much of the measured distortion value is actually added by the measuring setup and how high is the effective value of the tranny and the panel.
In any way the larger panel was measured with less than 0.2%@95dB@4m above 100Hz and the smaller one limits above 110dB@4m, measuring less than 0.3% above 200Hz. Both panels distortion mainly consists of K2.


@EL´OL
The new Final are constant voltage devices with a inherently non linear drive system...a proven way to generate distortion...so there´s no need to modify them at all
"BTW, what I find boring about ESLs is mainly the transients and the poor integration with a dynamic bass. I would like to listen to a magnetic planar (not a muddy maggie) with ESL midrange."
Those who listened to my systems were atonished about the reproduction of transients and the good integration of bass ;-)
Dynamics like a big horn system combined with the exceptional precision and resolution of ESLs, combined with the seemingless integration of bass like a FR.
One of the reasons is to have a highly efficient panel crossed over not too low to a dipole bass (which measured below 0.2% distortion above 25Hz @95dB@4m too!) ;-)

I must admit though that it sounds best, when a SE triode amp wo. feedback is driving the panels ;-)

jauu
Calvin

[el`Ol]

Originally posted by Calvin

Those who listened to my systems were atonished about the reproduction of transients and the good integration of bass ;-)
Dynamics like a big horn system combined with the exceptional precision and resolution of ESLs, combined with the seemingless integration of bass like a FR.

I admit it is problematic to generalize with my very limited listening experience.