07-07-14: BifwynneBifwynne, here is some more material for you to read that will address the phase coherency question you had yesterday (7/6/14):
.....I still wonder out loud whether speaker inductance as a function of frequency response in fact remains constant within the speaker's pass band. Indeed ... even if speaker inductance remains constant as a function of frequency, wouldn't that also impact phase coherency?
http://greenmountainaudio.com/speaker-time-phase-coherence/
this is an article that Roy J wrote for Audio Ideas Guide back in 1997. A small cut & paste from this article:
"The causes of phase distortion
Time delay is the natural consequence of making something vibrate, whether it's electric fields or material objects. In speakers, only three things can cause time delays:
◾The moving elements (the drivers -- woofers, midranges, tweeters);
◾Their distances through the air to the listener; and
◾The crossover circuit.
Let's go over the cause of motion-based time delays first. Different drivers (round, square, flat) have an inherent amount of phase shift, related only to each one's natural resonant frequency. One analogy is a weight hanging from a spring. If you move the other end of the spring up and down very slowly, the spring does not stretch and the weight follows your motion exactly. The phase shift between your applied force and the weight's motion is zero. The moving system is in a 'minimum-phase' mode. If you move more rapidly, the spring starts to stretch and contract -- and the weight no longer follows your driving force. It moves with a different phase.
......"
there's a lot more to read but I believe that you should read the section "The Causes of Phase Distortion" to answer your question....