Multiple simultaneous sound channels (sources) with X.org and Envy24 (M-Audio Audiophile 2496)

[Scott Spare]

Multimedia gurus,

I am looking for advice about the best way to handle the following
situation:
Playing sound with any two apps at the same time causes errors, sound
stuttering and / or hangups.

So far, I've tested and confirmed this problem under the following
conditions:
-Amarok is playing music and Pidgin tries to make noise to tell me someone's
online.
-XMMS is playing music and Pidgin tries to make noise.
-XMMS and Amarok are both playing music at the same time.
-Shell-FM is playing music and Pidgin tries to make noise.

Expected behavior:
Simultaneous sounds play simultaneously.

Errors received:
pcm0: play: dsp0.p0 play interrupt timeout, channel dead
pcm0: play: dsp0.p1 play interrupt timeout, channel dead

What I have tried so far:
-I've enabled autovchans in sysctls: hw.snd.maxautovchans: 4.  This did not
help.
-Reading more, I became a bit confused about a message regarding the driver
(or at least the hardware) supporting multiplexing natively

>* > it is a feature, not a bug and it is really great feature, so should be
*>* > removed from the list with bugs. Envy24(1712) has very precise 36bit
*>* wide
*>* > hardware mixer, which is superior that vchans (software sound mixer in
*>* the
*>* > kernel). the driver supports Envy24(1712) hardware mixer, so up to 10
*>* > channels (5 stereo pairs) can be playback simultaneously and that is why
*>* no
*>* > software sound mixer (vchans) is needed.

(This is from http://lists.freebsd.org/mailman/htdig/freebsd-multimedia/2006-July/004560.html)
*

-So I installed OSS, thinking that maybe it could solve my multiple audio
source problems, but got the same problem - stuttering sound when playing
multiple sources, followed by instability.  I later learned that OSS hadn't
loaded correctly, and didn't support multiple sound channels on FreeBSD
anyway, and I am trying to avoid running a heavy sound server if
possible...  so without any luck with OSS, I've now uninstalled it.  I'm
open to suggestions.  Does anyone know how PC-BSD handles sound?  Maybe
they've got it right for the desktop?  There's ALSA, ESD, ARTS, OSS FreeBSD
version via ports, OSS 4Front version, vchans, hardware multiplexing and
more.  Pretty confusing.


Here's some info about my setup:

*sndstat:*
FreeBSD Audio Driver (newpcm: 32bit 2007061600/i386)
Installed devices:
pcm0: <Envy24 audio (M Audio Audiophile 2496)> at io
0xccc0:32,0xcca0:16,0xcc80:16,0xcc00:64 irq 10 [MPSAFE] (5p:0v/3r:1v
channels duplex default)

*uname:*
FreeBSD 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #0: Mon Nov 10 02:00:54 EST
2008     :/usr/obj/usr/src/sys/STRIPPED  i386

*pciconf:*
1465-    vendor     = 'VIA Technologies Inc (Was: IC Ensemble Inc)'
1528:    device     = 'ICE1712 Envy24 Multichannel Audio Controller'
1592-    class      = multimedia
1620:    subclass   = audio

I can provide more info if it helps, just let me know.

Please advise?
Scott
http://www.scottspare.com