Path: utzoo!attcan!uunet!lll-winken!elroy.jpl.nasa.gov!ames!coherent!dplatt
From: dplatt@coherent.com (Dave Platt)
Newsgroups: comp.sys.mac
Subject: Re: Mac IIcx & STEREO Sound
Message-ID: <47517@improper.coherent.com>
Date: 22 Feb 90 18:28:31 GMT
References: <$&%#!$&@rpi.edu>
Reply-To: dplatt@coherent.com (Dave Platt)
Distribution: comp
Organization: Coherent Thought Inc., Palo Alto CA
Lines: 45

In article <$&%#!$&@rpi.edu> frontah@pawl.rpi.edu (David J Sotnick) writes:
> One thing that never gets discussed when comparing a Mac II with an '030 Mac,
> is the fact that the 030 Machines have a stereo sound chip.

So does the Mac II.

> Does anyone have any technotes or programming informtaion on how to utilise 
> that chip? I would like to be able to play stereo samples at 44.1KHz from
> my Mac IIcx. ANY help would be appreciated. I plan to use Lightspeed C.

Sigh.  Although the Mac II family has been out for almost three years now,
the MacOS Sound Manager _STILL_ does not provide any way to play stereo
sound.

As you may have noted, the Sound Manager chapter in Inside Macintosh V
is... shall we say... somewhat unclear in a few places :-(.  Apple
released an updated version of this chapter last year... it's available
as a Microsoft Word document, and can probably be FTP'ed from Apple.com
or from SUMEX-AIM.Stanford.Edu.  The updated chapter clarifies many of
the formerly-fuzzy issues involved in dealing with the Sound Manager,
lists a whole bunch of bugs, and summarizes the features which simply
do not work in the current Sound Manager.

Stereo sound is one of them.  The chip can handle it (I've heard some
very impressive stereo demos), but the Sound Manager won't let you play
one waveform through the left channel and a different one through the
right.

As far as I know, Apple has not released any technical description of
the chip interface which would make it possible for individual hackers
to work around these limitations.  I could well be wrong... Partners
may have access to this info... but I haven't seen any such data
available through APDA, for example  Apple actively discourages people
from accessing the Mac hardware directly... "Use the appropriate traps
and Managers" seems to be the party line... but in this particular
case, the Manager doesn't do the job.

>SNARL<.  Apple ads and technical-descriptions which describe the Mac II
family as having "stereo sound capability" are skating on the fine edge
of false representation, I think.
-- 
Dave Platt                                             VOICE: (415) 493-8805
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