> This by the way is why I think high sample rate files are popular with > some people, its not that the file has more high frequency information, > but that the DAC is using a better sounding filter at that sample rate.
I have a theory that any filter steep enough to get from 0dB at 20kHz to -80dB at 22kHz will somehow be detectable to the human ear/brain. It needs a lot of FIR taps to make such a filter, and the ultrasonic pre-ringing that is likely to be associated with linear-phase design may be somehow detectable. (See attachments.) Such a filter is needed twice: firstly to allow the track to be down-sampled to 44.1kHz from the studio format for distribution; secondly, a similar filter is needed as part of the up-sampling process in the DAC as described by John S. Intuitively, I expect the convolution of two such filters to be harmful, not due to removal of high frequency information that we cannot detect, but in the way the brain interprets wavefronts and timing cues. This is partly the theory behind so-called apodizing filters. I'd be interested in any justified assertions as to why this could or could not be an impairment worth addressing. +-------------------------------------------------------------------+ |Filename: mag_plot.jpg | |Download: http://forums.slimdevices.com/attachment.php?attachmentid=13212| +-------------------------------------------------------------------+ -- dsdreamer ---------------------- "Dreamer, easy in the chair that really fits you..." ------------------------------------------------------------------------ dsdreamer's Profile: http://forums.slimdevices.com/member.php?userid=12588 View this thread: http://forums.slimdevices.com/showthread.php?t=94352 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
