How do we measure dynamics?

[Ooidal]

This can, by itself, create nonlinearities in the very air (air is not a linear transmitter of sound, and the distortions become quite evident above 120SPL or so, and measurable below that.)

I am not keeping up with most of this thread but this bit has intrigued me. If air is not a linear transmitter of sound is there a material out there that is or is at least the most optimal?

 

[j_j]

I am not keeping up with most of this thread but this bit has intrigued me. If air is not a linear transmitter of sound is there a material out there that is or is at least the most optimal?

The mathematical description of air propagation will show you the problems. It's probably not a discussion for this forum, but nonlinear acoustics is a thing, just not one that's good to have around ears.