Subject: [linux-audio-dev] suggestion for developers: "real" quad-channel output on an SBlive
From: Josh Whiting (jwhiting_AT_hampshire.edu)
Date: Tue Nov 20 2001 - 07:12:42 EET
hi all
i am a list-lurker, primarily a windows multimedia user, but with an
interest in audio software development and hence an interest in linux.
anyway, i have and idea that has been provoked by my recent explorations
into quad-channel audio output. Basically, the idea is to write a driver to
interface with the SB-Live EAX bus that converts the SB live into a
more-or-less 'true' four channel output device. How? 1 - setup two stereo
virtual audio input ports, 2 - assign each channel a status in the EAX bus
as a sound source with a specific spatial position so as to emulate the
direct dispatch of each channel to its respective output in the dual-output
SB live DACs. You may not even need two virtual ports, as you could
probably assign the main output (sb live wave out) to the front stereo
outputs and then just send the second (virtual) stereo stream to the rear
outputs.
and bam - the SB live is now a (low cost) four channel output device,
overcoming the (idiotic, painful) limitations imposed by creative's
engineering of the board only support a single stereo output even though the
card has two of them...
The only problem I forsee with this is the possibility that the sound from
each channel could appear quietly in the other three channels as a potential
result of the EAX spatialization algorithm. But perhaps if you turn the
reverb to nil and set each channel as a narrow sound "cone" (you can do this
with EAX) there would be no interference (hopefully).
anyway, I'm a musician using windows, and I'm thus actually more interested
in a device driver for windows that does this. I could set something like
this up using DirectCsound (which supports EAX) but it would not sport the
realtime dual-stereo wave input and would also be a total cpu hog (as csound
tends to be). But, I thought i'd throw the idea out there and see if anyone
is inspired... let me know if you pick it up, i'm interested in the
outcome.
josh whiting
jsw98_AT_hampshire.edu
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