In Reply to: RE: I quit, after I found MOG...................... posted by Cut-Throat on November 28, 2012 at 15:58:28:
Redbook CDs’ two channels of audio data (not including overhead) are pulled off the disc at a rate of just over 1400 Kbps. Just keeping it simple, a 320Kbps MP3 preserves less than one-quarter of the music, the rest is thrown away. The differences in sound between CODECs are due to the tastes of the designers in choosing what gets thrown away, nevertheless, it must be thrown away.
Spectral analyses by John Atkinson of complex test tones recorded and played back at various MP3 bitrates show they are reproduced correctly, but the noise floor at higher frequencies is around -85dB, improving at lower frequencies to better than -90dB. A lot of spurious “sidebands” are introduced in the test signals. He concludes that both MP3 and AAC introduce fairly large changes in the measured spectra, even at the highest bitrate of 320 Kbps used in his tests. He basically set out to find why MP#s sound bad to his ear, so consider his prejudice.
There has been an industry conspiracy, IMO, backed by some flawed testing, "proving" that high-bitrate MP3 and slightly lower bitrate AAC are “transparent,” i.e. that they are indistinguishable from the WAV file of the same material (presumably 16/44.1 LPCM). “CD Quality” is the phrase bandied about all the time. I think it's very misleading.
My experience suggests the audibility of artifacts on high bitrate MP3s can be heard reliably provided you have 1.) good listening conditions 2.) sufficient quality speakers such that they do not introduce order-of-magnitude-higher nonlinearities, effectively swamping the MP3 garbage and 3.) reasonably trained ears. We unfortunately get what the generic consumer asked for. Deutsche-Grammophon for its classical downloads uses MP3 at 320 Kbps, apparently feeling this is “good enough.” I think they sold out. Dr. Dre agrees- must be right.
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Follow Ups
- I find that surprising - mr.bear 11/28/1219:09:30 11/28/12 (2)
- Well......... - Cut-Throat 04:05:53 11/29/12 (1)
- Will do that (nt).. - mr.bear 18:10:06 11/30/12 (0)