> And those very good brick wall filters _will_ have a considerable group
? The only way they'll have any group delay is if they're hybrids
using a minimum phase section to save on gates. The linear phase
section is going to do the heavy lifting in any modern design... if
there's any AA filter at all. Once all the hash has all been shaped
into the >1MHz region, many designs don't bother anymore.
Despite the Pono and Meridian press releases, minimum
phase/"apodizing" AA filters are not actually desirable.
On Sun, Mar 16, 2014 at 2:39 PM, Gene Heskett wrote: