AW: [sdiy] some observations : audibility of phase distortion

[Nils Pipenbrinck]

Czech Martin wrote:

> During the vacations I made some experiments.
> Unit pulses and a short drum sample were filtered
> with a discrete all pass filter. I checked that the amplitude
> of that filter was flat, but phase was very nonlinar.
> The nonlinearities where arround 100-400 Hz.
> I tried 2nd , 4th and 6th order.

> The signals were visibly distorted, but:

> I couldn't hear a difference....[snip]


That's ok... You shouldn't hear much difference if you use complex signals
such as a drum-sound. I could be completely wrong, but I think I remember
that different frequencies travel at different speeds through the air. Think
about a thunderstorm. First comes the bang, then the rumbling.

So you hear phase-distortion all the day. Everything you hear is
phase-distorted based on the distance to the soundsource. Our brain
compensate that.

For more simple signals such as a sawtooth or so you might notice a slight
change in timbre.

  Nils