I have used the original Quad, Acoustat 2+2, and Martin Logan CLS as midrange reference transducers over the past 27 years. I like their lack of cabinet resonance and single-driver coherence; however, they all exhibit tremendous dynamic compression from a mechanical standpoint. At Cal Tech, we used a laser interferometry setup to measure the dynamic range as referenced to excursion potential vs. voltage. As the electrostatic diaphragms are stretched very tightly and have no elastic edge surround, they have a finite limitation on excursion potential, no matter how much more voltage you input. Initially, the diaphragm will move on a 1:1 scale, but rapidly, the excursion does not follow the input voltage, resulting in a very high degree of compression of the signal. This is the source of "lack" of dynamic range that most listeners pick up on. Most cone systems do not compress until very high volume levels are reached.
Albert Von Schweikert
Albert Von Schweikert