drmatt wrote: > That guy likes to talk about himself. > > Seems somewhat disingenuous to attempt to ascribe the "distortion" of > the whole A-D-A digital recording and playback chain of a signal at > -90db to the digital system itself, rather than the whole chain. And I > wonder how bad an LP would reproduce the same signal? > > They didn't appear to understand dynamic range.
The article makes a lot of claims about this Noel Keywood. Would be interesting to see these articles like: 40% THD: Compact Disc We explode the low distortion myth (May/June 1985) to see what these people were on about. Perhaps this is the best clue: -"Noel admitted that just stating that CD had 40% distortion was about as meaningful as trying to say that it had negligible distortion, but he pointed out that digital differs in one vital way from analogue. And thats in the fact that with analogue, as the signal level gets louder distortion goes up, whereas with digital distortion drops as the level goes up. At full volume, it is very low indeed, around 0.001%. But at the levels we mostly listen at, distortion is far from low. His tests showed that the ear can easily hear signals recorded at a level of -65dB below full output (0dB) where he measured distortion on the CD player at around 4% a far cry from 0.001%! At -90dB, we got a distortion level of 38.5% THD [total harmonic distortion]. He also pointed out that where with analogue distortion harmonics are 'even order' and pleasing to the ear, all of the significant distortion on digital is 'odd order' and extended right up to 20kHz, which is particularly nasty to the ear."- So the dude measures distortion levels in a 16-bit format at -65dB. Very low level! So he's basically only using the lowest 6-bits! Is that what they did? And given that CD players / DACs in 1985 were incapable of full 16-bit accuracy, it looks bad with at best 36dB dynamic range. And lots of noise, etc... And says this is is a flaw of the digital system!? Indeed. These guys should try recording some -65dB signal below the peak allowable amplitude on a piece of vinyl and tell us how it sounds - if it's even audible above the surface noise at all! Archimago's Musings: (archimago.blogspot.com) A 'more objective' audiophile blog. ------------------------------------------------------------------------ Archimago's Profile: http://forums.slimdevices.com/member.php?userid=2207 View this thread: http://forums.slimdevices.com/showthread.php?t=105507
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