Originally Posted by VirusKiller
Thanks Charles. I did realize that minimum phase filters also ring, but what I wrote did kind of imply that it was a brick wall filter problem (which is what JA was describing).

Hi VK,

My take on what JA was saying was that any ringing at 22+ kHz shouldn't be audible and he was therefore surprised that making *any* changes to that ringing -- killing it, moving it before the impulse, moving it after the impulse, whatever -- shouldn't be audible. So I think he was surprised by the improvement made by Meridian's filter, which in theory shouldn't make any *audible* difference. Especially for those who are old enough that we can't hear past 20 kHz anymore...

But theory and practice are two different things. I've heard a clear difference by changing the bandwidth of a power amp from 150 kHz to 250 kHz. And the really weird thing is that we had to extend the bandwidth of that design to 250 kHz to get it to sound as extended and open as a different design with a 100 kHz bandwidth. Go figure....

Cheers,
Charles Hansen
Ayre Acoustics, Inc.