[NTLK] Analog / Digital / MP3 / so forth

From: R Pickett (emerson_at_hayseed.net)
Date: Tue Oct 30 2001 - 18:49:46 EST


Lots of comments on whether "MP3 sound" is equal to "CD sound." Well,
the MP3 format allows for a huge range of compression rates, so that
there's really no such thing as "MP3 sound." I defy any person,
anywhere to hear the difference between a 320K MP3 encoded by a good
codec, and the CD track it was taken from, in a blind test. I defy any
person, anywhere to listen to a 32K MP3 and tell me it's acceptable for
music. "MP3 sound" isn't a single thing. Even at the 'default' 128K,
there are all sorts of options as far as VBR encoding, joint-stereo, and
so forth, that mean just talking about a single _bitrate_ doesn't make
sense. There's no really sane way to make black/white statements about
anything more general than specific MP3 streams versus their specific
sources.

That follows for analog versus digital. Every single mass-market analog
format is destructive on playback. Tapes shed oxide, vinyl ablates.
Every time you play it back, it sounds subtly worse. Digital media
(tapes excluded) don't suffer from this. It sounds the same every
time. Is that 'as good?' Your mileage may vary. I saw a comment
comparing vinyl copies of classical albums to CD's of the same material,
calling the vinyl 'warm' and the CD 'tinny.' That may well be the case
for a combination of several reasons:

-- Many mastering houses, especially classical ones, are employing the
same mastering engineers that they have for the past 40 years. Good for
them, except that these fellows often apply an upper-mid boost during
mastering that has always been used to get around some of the physical
vagaries of vinyl as a medium. Sounds great on vinyl, sounds shrill on
digital media that don't have physical attributes that change the sound.

-- Old albums start to wear down their mid- and high- frequency content
with repeated playbacks. This 'smearing' of the content can be
perceived as a 'warmth,' in the same way that tube aficionados enjoy the
subtle high-frequency distortion of tubes as 'warmth.' To compare to a
CD of the same material, it would be necessary to get a brand-new copy
of the vinyl. You might be surprised at how 'bright' and 'harsh' it
sounds fresh off the press.

-- The only real way to compare audio sources that are similar (as
opposed to 2-inch tape versus AM radio) is with AT LEAST a single-blind
test to get biases (personal biases, not tape biases...) out of the
way. Preferably double-blind. I've worked in the MI/recording industry
for something like 10 years, and in that time, I've seen scores of
double-blind tests debunk almost 100% of the 'golden ears' guys who had
been doing their own tests at home with personal prejudices. A few
exceptions were people who get paid full time for their ears; Flood
(former NIN/etc engineer) and Ben Mink (kd lang) come to mind as people
who really CAN hear the difference. But they are the geniuses. Us
normal folk mostly CAN'T hear the difference.

Bottom line? Good digital and good analog and good MP3 are for the most
part indistinguishable except in pathological cases, and when we're
talking about personal walk-about MP3 players, those are NOT those
pathological cases. I'll be glad to set up a single-blind test for
anyone who wants to come by my house and challenge that....

-- 
R Pickett           The people that once bestowed commands, consulships,
Hayseed Networks    legions, and all else, now meddles no more and longs
emerson_at_hayseed.net eagerly for just two things  --  bread and circuses.

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