wattage

Brauser - you are exactly right. The amount of power (watts) needed to give the impression of adequate sound pressure levels is less than you think. If the signal applied to your loudspeakers is not phase coherent, it will seem to lack "punch". If the listener then turns the volume up to achieve this "punch", it is only an attempt to compensate for the incoherent signal. What you end up with is a louder version of an incoherent signal. If you have a coherent signal then the "wattage" becomes more efficient. In other words if you have 2 systems, one coherent and one with phase or time domain errors, driving them both at exactly the same measured wattage, the coherent system will sound noticeably louder (at least 3+ db). Timing is everything.

Roger

Signal applied "not phase coherent"?. Do you suggest that amplifier somehow shifts phase in the audio frequency range causing reduction of perceived loudness ???

Yes it does. See the white paper on distortion.
There is a link at www.h-cat.com

The "punch" is diffused by very small changes in velocity.
This spreads the energy of a percussion event over time.

Roger

For more information...
This link should take you to the white paper on distortion and timing issues...

http://h-cat.com/whitepaper.html

Roger

While I agree that all electronics causes some phase shift of the music signal, I believe that the most flagrant violator of phase distortion is the speaker. Once the listener has corrected this then I would venture to fix the phase shift from the electronics.