On Wed, 11 Mar 2015 19:46:25 GMT, (Don Pearce) wrote:

On Thu, 12 Mar 2015 06:40:05 +1100, Trevor Wilson
wrote:


**Well, it would, wouldn't it? Phase shift and all that.... The human
hearing system is exquisitely sensitive to phase shift.


The human hearing system is essentially totally deaf to phase shift.

+1

I've seen an experiment in which the phase of the harmonics of a
square wave was cyclically shifted. You could see the waveform
changing shape on a scope. Even with the picture in view, it was
impossible to hear any change in the resulting sound.

I was going to mention the effects of phase shift on the harmonics of
a 500Hz squarewave played back from analogue magnetic tape where,
despite the oscilloscope display showing it looking nothing like a
square wave, it still sounds just like the original squarewave. Also
the trick, when dubbing copies from a master tape, of playing the
master and slave recorders in reverse to cancel the effect of the
phase shifts, largely restoring the waveshape back to a semblence of
'squareness'.


Deafness to phase shift is the reason why Orban's Optimod system is
able to operate inaudibly.


I guess the phase shift sensitivity reference Trevor is thinking of
is in relation to stereo detection of the direction of sound sources
rather than the percieved quality of the sound by each individual ear.
--
J B Good