In article ,
"William Sommerwerck" wrote:

The point is entirely about * cone excursion* above resonance as a
function
of drive frequency for fixed AC drive voltage. Obviously a cone does not
follow the actual drive voltage wave - or the excursion and all
frequencies
would be the same.

Once you work out the simple relationship is between drive frequency and
cone excursion when the cone's mass dominates the game - you have it.

How dare you answer a criticism courteously -- what's the world coming to?

I'll check my books on acoustics about this.

Check your physics book, too, recalling (as Phil said), that a speaker
is a mechanical system operating *above resonance*.

You can simulate this by hanging a fairly heavy weight from a rubber
band. Hold the other end of the band (with the weight hanging down,
stretching the rubber but *not too much*). Move your hand up and down.
Below resonance, the weight follows your hand, with constant
displacement, no matter the frequency. Above resonance, your hand goes
down while the weight is coming up, and the faster you move your hand,
the smaller the weight's excursion gets. That's the domain a speaker
works in.

It is this reduction in excursion as frequency increases that makes a
speaker *automatically* have a constant volume velocity (constant output
level) regardless of frequency. The cone excursion drops by a factor of
four for every octave increase in frequency.

But insofar as speaker phasing is concerned, as long as they are both
the same, it doesn't matter much, because in general, you have no idea
what happened to the signals before they got stuck on that CD (or
whatever).

Isaac