I suspect that with speakers, signal response varies by frequency AND amplitude. So you won't be able to get away with an adjustment function that uses frequency alone.

You're right - what you're describing is nonlinearity (where wattage doesn't map in a straight line to displacement), which is what THD+N and IMF ratings indicate. It is possible to adjust for this too (class T amplifiers do this I think) but it's much more difficult. The difficulty here, I suppose, is actually building measurement devices which have very low distortion (expense expense!)

Something that springs to mind is that speaker which uses ultrasonics to direct sound into a very narrow cone. The nonlinearity of air is used predictively to generate (a few feet in front of it) lower audible tones with sound quality similar to that of an ordinary speaker. You could apply the same techniques to ordinary speakers to get lower distortion - if you can find a suitable measurement device. There are patents (pending) for the ultrasonic speaker, but I don't know if they are generalised or not.


- John (from empeg)

(The above may not represent the views of empeg :)