Home Propeller Head Plaza

Technical and scientific discussion of amps, cables and other topics.

[ Follow Ups ] Thread: [ Display  All  Email ] [ Propeller Head Plaza ]
[ Alert Moderator ]

May not be undesirable

Some time back, another poster here implemented an FFT-based CD upsampling approach and was pretty pleased with the results. IIRC, for each track he converted the data to double precision floating point, zero padded each track out to a power of two number of samples, FFT'd the track, applied the ideal brick wall response, added zeros to 4x oversample the data, IFFT'd it back, removed the padded samples, dithered down to 24-bit fixed point, and burned the resulting 24/176.4 track to a DVD-A. Or something like that anyway. Obviously, it's not something that can be done in real time with current technology, but I think it's as close to mathematically ideal as we can get.

BTW, I think it's questionable that reducing the spread of the ringing is desirable. I think a lot of people like Todd who complain about seeing ringing on an impulse response, step response, or square wave mistakenly think that it is an artifact of the imperfect nature of FIR filters. When in fact, the ringing is simply a product of band limiting - by whatever the means. In a properly band-limited square wave, the ringing is supposed to be there.

Dave



This post is made possible by the generous support of people like you and our sponsors:
  Schiit Audio  

Follow Ups Full Thread
Follow Ups
You can not post to an archived thread.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]