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From: zech@leadsv.UUCP (Bill Zech)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Sound Blaster with Windows
Message-ID: <12512@leadsv.UUCP>
Date: 15 Aug 90 20:56:28 GMT
References: <1990Aug7.153600.10175@IRO.UMontreal.CA> <28112@unix.cis.pitt.edu> <1990Aug14.042014.12967@Neon.Stanford.EDU>
Reply-To: zech@leadsv.LEADS.LMSC.COM.UUCP (Bill Zech)
Organization: LMSC-LEADS, Sunnyvale, Ca.
Lines: 29


I have played music and voice files with the SoundBlaster under Windows 3.0
with some success.  To play voice files, you need to increase the DMA
buffer size (specified in system.ini, I think) to (no more than) 64K.
The default size is much smaller, and thus limits the length of the
voice file it can play.  This is the ONLY case where DMA is involved,
not music files.

For music files, the play OK in a forefround window, but not very
well in background.  The CMS and Adlib music playback programs both
reprogram the system timer to tick faster than the normal 18.2/sec.
This is done to accurately measure the music time signature.  The
timer ISR is the guy that fiddles with the board's music register
file.

Windows 3.0 apparently multitasks DOS programs via a simple time-slice
algorithm, and anybody familiar with sampling theory can see how
this will produce bogus results with the music playback code.  The result
is very intermittent notes.  A tried a variety of settings for the 
foreground/background values without much luck.  I don't have the
jukebox program, so I don't know how well that would work if loaded
prior to running Windows.  Perhaps better.

BTW, I have developer's kits for both the Adlib board and the Sound
Blaster.  They are better than nothing, but I think they are rather
poorly packaged and documented for the money.

- Bill
zech@leadsv.com