Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!osu-cis!killer!texbell!bellcore!clyde!watmath!softart!riml
From: riml@softart.UUCP (Research in Motion Limited)
Newsgroups: comp.sys.next
Subject: 16-bit Digital Sound: FP or int?
Message-ID: <44@softart.UUCP>
Date: 11 Nov 88 15:06:27 GMT
Organization: Softart Microsystems Inc., Waterloo Ont. Canada
Lines: 35

[Has anyone wondered about sound fidelity at low levels?]

Here's a set of questions for inquiring minds.

1) Is the "CD" quality 16-bit output of the NeXT using 16-bit INT
   words, or 16-bit Floating point words? (i.e. 3-bit exponent+13
   bit mantissa)

2) Can anyone tell me the exact specification for the CD/DAT digital
   format, or can they point me to documentation available at a library,
   or can they forward this message to the appropriate person or newsgroup?

3) Can anyone tell me if there is a manufacturer of floating point
   Analogue to Digital converters and Digital to Analogue converters?

The reason I ask these questions is simple.  I have been convinced that
the "CD" digital encoding uses floating point.  Why?  If it didn't, low
level signals would be hopelessly distorted due to the lack of information
content in a LINEAR encoding at low levels.  

Thus, LINEAR 16-bit output D/A systems will NOT produce "CD" quality sound.

There has been a lot of hype recently in musical instrument circles about
"16-bit" samplers and reproducers giving "CD" quality sound.  However, 
very few manufacturers discuss the encoding scheme.  Naturally, based on
my assumption above, LINEAR encoding is BAD.  

If my assumptions are incorrect, I would be happy to be told so by an
INFORMED source.  I would also be ecstatic since 16-bit FP D-A converters
are EXPENSIVE!  (I haven't found ONE 16-bit FP A-D converter!)

Michael A. Barnstijn,         USENET:  {uunet|sun|decvax}!watmath!softart!riml
VP Software Systems           PHONE:   (519) 888-7465
Research In Motion Limited    SLOMAIL: Suite 6, 465 Phillip St., Waterloo
                                       Ontario, Canada   N2L 6C7