[sdiy] group delay (of filters) and listening

[Czech Martin]

good description. But then the group delay difference is allready in 
the 1ms range. If this is driven further, you really get the impression that
e.g. the treble sound comes earlier than the bass sound.

But not all systems have such large differences. So in many cases 
there is no difference in performance, even if the phase is not linear.


m.c.

-----Original Message-----
From: mirwin at qouest.net [mailto:mirwin at qouest.net]
Sent: 05 October 2004 15:32
To: Czech Martin
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] group delay (of filters) and listening


Martin (and list),
I have done some experiments with long allpass chains (including up to 
24 first-order analog allpass stages, identical sections). If you listen 
to a narrow pulse (say one millisecond) the non-constant group 
delay (dispersion) is quite obvious - the "click" turns into a short 
"blip" with rapidly descending pitch. The effect on recorded music is 
much less obvious, more so with fewer allpass stages. 
Mike