dsdreamer;699293 Wrote: > 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.
Try for your self , in the 192k is harmful tread I managed to get the SoX resampler installed at my desktop and took a couple a what it bought is good sounding 24/96 files and converted to a number of rates including 16/44.1 ( I used files of true digital PCM recordings at >= 24/96 all else would obscure the experiment, the fact that a large number of hirez recordings are "fakes" would not help ). I'm not finished with that experiment yet . My theory is that there may be at least some recording where it matter, but I have not been able to tell a conclusive difference yet . It's not impeccable science it is sort of semi blind I just shuffle a bunch on copies of converted and non converted files and just guess what I'm listen to. One have listen repeatedly ,hearing throw curve balls you sometimes think the same file sound different ,but that's just how the brain works. But you need not to look further than Boston audiophile societies famous inline resampling experiment for evidence on how hard this is to detect this in practice even if the ringing looks like it does. ( the put an 16/44 AD-DA device in a hirez playback chain and besides some rare case of the higher noise of the equipment being detachable in someone's rig no one heard anything ) -- Mnyb -------------------------------------------------------------------- Main hifi: Touch + CIA PS +MeridianG68J MeridianHD621 MeridianG98DH 2 x MeridianDSP5200 MeridianDSP5200HC 2 xMeridianDSP3100 +Rel Stadium 3 sub. Bedroom/Office: Boom Kitchen: Touch + powered Fostex PM0.4 Misc use: Radio (with battery) iPad1 with iPengHD & SqueezePad (in storage SB3, reciever ,controller ) http://people.xiph.org/~xiphmont/demo/neil-young.html ------------------------------------------------------------------------ Mnyb's Profile: http://forums.slimdevices.com/member.php?userid=4143 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
