Phase Distortion - Speaker/Amplifiers

In speakers, it also refers to the ability of drivers to appropriately synchronize push/pull.

http://www.thielaudio.com/THIEL_Site05/Pages/FAQs/faqtimephase.html

Here is a layman explanation. It is full of speculation (much of which is doubtful) but the basic explanation is correct and there are some further links.

phase Distortion

IMHO phase distortion is way over rated.For sure there are extremely subtle audio effects but that is true of any change in listening space. One must remember that we hear frequencies NOT waveforms - changing phase can alter how the audio signal behaves overall as it interacts with the room - multiple reverberations will all cause phase shifts.

The key is to have gentle change in phase as a function of frequency. A marked 180 or 360 degree shift at a specific point in the spectrum will indeed be audible across the midrange as it will change the timbre of certain instruments very slightly.

The author's complaints about B&W are conflating two very different effects - by moving the crossover to 4KHz, B&W are dramatically altering the midrange into a narrow beam of sound with reduced room reflections (think a flashlight versus an ordinary lightbulb) and this effect will be far far more audible than any slight change in phase. This is an example that shows how easy it is to jump to false conclusions in audio due to the fact that many interrelated things are going on and what one hears differently after changing a setup can easily be something other than the presumed cause.

Although this subject is way over rated (much less important than many other terrible deficiencies in most loudspeakers), if you want the best then get an active speaker!

It appears that phase distortion is primarily the result of crossover networks in multi driver speakers which is why headphones and single driver speakers have less phase distortion.

On the surface it seems that a network that results in 180 degrees (2nd order?) of phase distortion could be corrected by simply by reversing the wires on the driver itself. It must not be that simple.

Any audible difference results from the individual drivers not all firing at exactly the same time.

In all cases the amplifier is "seeing" the cumlative effect of entire speaker so what does an amplifier do with a phase shift? It seems that if an amplifier is really just transmitting a series of + and - pulses it's already operating at extremes so why would phase shifting matter?