Super Filter = No filter

[Sean Costello]

Bissell, Harry wrote:
> 
> There have been some studies that indicate that phase is important (and some
> that say that its not) To get a particular waveshape i.e. square it is
> important to sum the right phase of harmonics. But could you hear the
> difference... I guess you could if the fundamental was at a reasonably low
> audio frequency. A scope would definatly show the wave as distorted. In the
> case of the square wave, if harmonics were shifted in phase, the rise time
> would be affected (maybe trashed). As far as the perception to human hearing
> ???  :-) Harry

My guess is that this would be important for nonlinear systems
(overdriven amplifiers, the cochlea, etc.), as the phase of the
harmonics will make a difference as to where the peaks in the waveform
are.  I also think it would make a difference with resonant filters -
for no really good reason, just a gut feeling.  As far as making a BIG
difference, probably not.

Phase is very important for proper reconstruction of signals from an
FFT; the phase of each frequency bin is tracked in a phase vocoder to
determine what the actual frequency in that bin is.

Sean Costello