From: larry@csccat.cs.com (Larry Spence)
Newsgroups: rec.music.cd
Subject: Re: Sony's SBM CD Mastering
Date: 29 Jul 92 08:00:25 GMT
Organization: Computer Support Corporation,  Dallas,Texas

In article <1992Jul28.135659.3796@news.cs.brandeis.edu> rardin@binah.cc.brandeis.edu writes:
>I received the August 1992 issue of Stereophile yesterday and found in it 
>a VERY interesting entry reporting on Sony's new Super Bit Mapping 
>(SBM) mastering technology. 

There was an article on this in the ICE Newsletter, too.  Similar hype.
"Super Bit Mapping" -- they've learned how to scale 20-bit samples to 16-bit
samples.  Will wonders never cease?  Sony is so good to us...

>Sony has come up with a way to provide "nearly 
>20-bit resolution from CD--without changing the CD format or existing playback 
>hardware." 

Simple fact - if the storage on and playback from the CD are 16-bit, the
most that can be done is to minimize the errors in the 16-bit samples.  The
maximum dynamic range is unchanged.  The size of a quantization "step" is
still 2^-16.

>The graphics in the article showed how

Uh oh.

>the new mastering technique 
>dramatically improves the encoding in at least 3 ways: (1) the noise floor is 
>lowered; 

Properly dithered 16-bit quantization noise is only audible if you crank the
volume so high that loud passages blow out your speakers... it's a non-
problem IMHO.

>(2) harmonic distortion generated by truncation in the standard 16-bit
>mastering is dramatically limited; 

But it's already inaudibly low, like 0.001% ... the major improvement
will probably be in tracking down decent analog masters and mastering
carefully.  I think the ICE article had some blurb about how they're
going to get the artists to approve the mastering EQ, etc.  What a novel
concept!

>and (3) a 100 Hz sinewave at -90 db
>_looks_ much more like a sinewave rather than the stairstep representation 
>generated by standard 16-bit mastering. 

...Great for all those bass subliminals at -90 db.

>The reviewer was very excited about the musical effects of this technology! 

Gosh, the ICE folks seemed thrilled, too!  I sure am glad they don't have any 
vested interest in sucking up to Sony that might cloud their judgement!

>The only problem is that Sony plans 
>to make the initial releases employing this technology on their Legacy label 
>with specially packaged CDs that have gold rather than aluminum reflective 
>surfaces (similar to Mobile Fidelity Sound Lab's Ultradiscs).

Odd, since gold metalization has no effect on the corrected bit stream...
They wouldn't be doing this to advertise in big, gold letters, "hey! this
CD is going to sound really great, 'cause we didn't master it from fourth
generation masters!" would they? %)

>Thus, the price is expected to be a steep $24. 

But it'll be worth it -- they're _gold_ discs, right?  Those are the best!

>However, the technology is eventually expected 
>to filter down to all CD mastering.

Sheesh.  Sony Classical has already put out several CDs that boast "20-bit
digital audio" at near-normal prices.  Oh, but those don't have grams and
grams of _gold_ slathered on them.  

-- 
Larry Spence
larry@cs.com
uunet!csccat!larry or sun!texsun!csccat!larry