dsdreamer wrote: > And earlier you said. > > > > Is your objection to having filters design using interpolated FIR > methods like the response I pasted below? Would this be considered > "complex" per your post above? Are you planning to use a filter that is > just a truncated (possibly windowed) SINC function instead? I'm just > trying to understand what you consider "simple" and "complex" > considering that what may be a mathematically -simple- approach may > require more computationally -complex- implementation to achieve > reasonable rejection.
Yes, I would consider a windowed SINC to be a simple filter. That's not to say that is actually going to be the exact function used. The ones that seem to have the most detrimental effect sonically are more complex functions designed to achieve higher stop band rejection with minimal hardware resources. The experimentation I have done seems to be pointing to not needing -120db stop band rejection. That something like a windowed SINC without a large number of taps which "only" achieves 60db rejection will sound better than the more complex function which achieves -120db rejection. That is not to say that -120db rejection by itself is bad, it's the implementation with small resources that seems to be the issue. I have tried a windowed SINC with a large number of taps to get -130db and it sounds great. The version with a much smaller number of taps with only 60db rejection also sounded excellent. I did not spend the time to see which sounded better, they were sufficiently close to each other that it would be difficult to tell them apart. But both of them were quite a bit better sounding than the hardware filter in the DAC chip which achieved -130db (at least according to it's spec sheet) John S. ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=98544 _______________________________________________ unix mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/unix
