@deludedaudiophile wrote:
"can you comment on room response of line arrays?
"... I expect that electrostatic speakers and large planar speakers must be fairly immune to these power compression / thermal modulation effects within limits?"
The room response of a given line-array system depends on the specifics. Obviously at frequencies where they approximate a line source the sound pressure level is falling off at about 3 dB per doubling of distance rather than the normal 6 dB per doubling of distance, not counting the contribution of reflections. There are of course tradeoffs to be juggled.
If small fullrange drivers are used, they beam moreso than most tweeters in the horizontal plane, resulting in a pretty big spectral discrepancy between the direct sound and the reflections. If tweeters are stacked alongside midwoofers, the frequency response in the crossover region changes significantly with the horizontal angle. If there is a central tweeter flanked north and south by stacked midwoofers, the tweeter may not approximate line source behavior as well as the midwoofer array.
All of that being said, with a line-source-approximating speaker the direct sound tends to be more dominant than with a point-source-approximating speaker, so I’m not sure how audible the aforementioned off-axis anomalies tend to be in practice.
Electrostatic speakers can have compression from transformer saturation at high power levels, and in extreme cases the transformer can overheat and melt. My impression is that in general they are less prone to compression than cone-n-dome speakers, but also less efficient and/or more difficult to drive, and in general will not go as loud as comparably-priced cone-n-dome floorstander speakers.
Single-ended planar magnetic speakers, those having magnets only on one side of the diaphragm, have a compression-ike mechanism because of the non-linear motor; that is, the motor strength decreases when the panel is further from the magnet, and increases when the panel is nearer the magnet, such that motor strength available for the higher frequencies is modulated by the lower frequencies. A push-pull motor structure eliminates this effect. I don’t know much else about compression mechanisms specific to planar magnetic speakers, but I am not under the impression that they are champions in the realm of dynamic contrast.
Loudspeaker/room interaction happens to be something that I give high priority to. The two types of speakers I sell are large, curved, line-source-approximating fullrange electrostats, and hybrid horn systems. I think full-range horn systems can be superb but they are inevitably larger than what I want to work with.
Duke