bad sound 5.1 - AC'97 Audio Controller - Linux Mint 9

[Boss32]

Surround 5.1 is very bad

main@main-desktop ~/bin $ osstest
Sound subsystem and version: OSS 4.2 (b 2003/201011031221) (0x00040100)
Platform: Linux/i686 2.6.32-25-generic #45-Ubuntu SMP Sat Oct 16 19:48:22 UTC 2010

*** Scanning sound adapter #-1 ***
/dev/oss/oss_ich0/pcm0 (audio engine 0): Intel ICH5 (24D5)
- Performing audio playback test...
<left> OK <right> OK <stereo> OK <measured srate 47974.00 Hz (-0.05%)>

*** All tests completed OK ***

main@main-desktop ~/bin $ ossmix
Selected mixer 0/ICH AC97 Mixer (ALC850)
Known controls are:
vol [<leftvol>:<rightvol>] (currently 75:75)
pcm [<leftvol>:<rightvol>] (currently 75:75)
speaker <monovol> (currently 56)
line [<leftvol>:<rightvol>] (currently 66:66)
mic <monovol> (currently 77)
cd [<leftvol>:<rightvol>] (currently 75:75)
igain [<leftvol>:<rightvol>] (currently 0:0)
aux1 [<leftvol>:<rightvol>] (currently 32:32)
phone [<leftvol>:<rightvol>] (currently 53:53)
mono <monovol> (currently 75)
video [<leftvol>:<rightvol>] (currently 50:50)
rear [<leftvol>:<rightvol>] (currently 75:75)
center [<leftvol>:<rightvol>] (currently 75:75)
micboost ON|OFF (currently ON)
recsel.left <MIC|CD|VIDEO|AUX|LINE|STEREOMIX|MONOMIX|PHONE> (currently MIC)
recsel.right <MIC|CD|VIDEO|AUX|LINE|STEREOMIX|MONOMIX|PHONE> (currently MIC)
mixext.centervol [<leftvol>:<rightvol>] (currently 100:100)
mixext.rearvol [<leftvol>:<rightvol>] (currently 100:100)
mixext.sidevol [<leftvol>:<rightvol>] (currently 100:100)
mixext.rear2linejack ON|OFF (currently ON)
mixext.center2micjack ON|OFF (currently OFF)
mixext.spkmode <FRONT|SPREAD> (currently SPREAD)
mixext.mix-lfe2front ON|OFF (currently OFF)
mixext.mix-rear2front ON|OFF (currently OFF)
spdout.enable ON|OFF (currently OFF)
spdout.adc/dac ON|OFF (currently OFF)
spdout.pro <Consumer|Professional> (currently Consumer)
spdout.audio <AUDIO|DATA> (currently AUDIO)
spdout.copy ON|OFF (currently OFF)
spdout.pre-emph ON|OFF (currently OFF)
spdout.rate <48000|44100|32000> (currently 48000)
spdout.vbit ON|OFF (currently OFF)
spdin.enable ON|OFF (currently ON)
spdin.monitor ON|OFF (currently OFF)
spdin.pro <decimal value> (currently 0) (Read-only)
spdin.audio <decimal value> (currently 0) (Read-only)
spdin.copy <decimal value> (currently 0) (Read-only)
spdin.pre-emph <decimal value> (currently 0) (Read-only)
spdin.mode <decimal value> (currently 0) (Read-only)
spdin.category <decimal value> (currently 0) (Read-only)
spdin.genlevel <decimal value> (currently 0) (Read-only)
spdin.source <decimal value> (currently 0) (Read-only)
spdin.channel <decimal value> (currently 0) (Read-only)
spdin.rate <decimal value> (currently 44100) (Read-only)
spdin.clock <decimal value> (currently 0) (Read-only)
spdin.signal <decimal value> (currently 0) (Read-only)
spdin.vbit <decimal value> (currently 0) (Read-only)
vmix0-enable ON|OFF (currently ON)
vmix0-rate <decimal value> (currently 48000) (Read-only)
vmix0-channels <Stereo|Multich> (currently Multich)
vmix0-src <Fast|High|OFF> (currently High)
vmix0-outvol <monovol> (currently 25.0 dB)
vmix0-invol <monovol> (currently 25.0 dB)
vmix0.pcm1 [<leftvol>:<rightvol>] (currently 25.0:25.0 dB)
vmix0.pcm2 [<leftvol>:<rightvol>] (currently 25.0:25.0 dB)
vmix0.pcm3 [<leftvol>:<rightvol>] (currently 25.0:25.0 dB)
vmix0.pcm4 [<leftvol>:<rightvol>] (currently 25.0:25.0 dB)

main@main-desktop ~/bin $ ossinfo -v3
Version info: OSS 4.2 (b 2003/201011031221) (0x00040100) OSS_HG
Hg revision: changeset: 920:232d0de71550, tag: tip, date: Tue Nov 02 23:45:15 2010 +0200, summary: Misc changes to ossplay
Platform: Linux/i686 2.6.32-25-generic #45-Ubuntu SMP Sat Oct 16 19:48:22 UTC 2010 (main-desktop)

Number of audio devices: 1
Number of audio engines: 6
Number of MIDI devices: 0
Number of mixer devices: 1


Device objects
0: osscore0 OSS core services
1: oss_ich0 Intel ICH5 (24D5) interrupts=779945 (779945)
2: oss_usb0 USB audio core services

MIDI devices (/dev/midi*)

Mixer devices
0: ICH AC97 Mixer (ALC850) (Mixer 0 of device object 1)
Device file /dev/oss/oss_ich0/mix0, Legacy device /dev/mixer0
Priority: 10
Caps:
Device handle: PCI08501849-0000:00:1f.5-mx01
Device priority: 10


Audio devices
Intel ICH5 (24D5) /dev/oss/oss_ich0/pcm0 (device index 0)
Legacy device /dev/dsp0
Caps: DUPLEX TRIGGER MMAP
Modes: IN/OUT
Engine 1: 0/Intel ICH5 (24D5)
Available for use
Engine 2: 1/Intel ICH5 (24D5) (vmix)
Available for use
Engine 3: 2/Intel ICH5 (24D5) (vmix)
Available for use
Engine 4: 3/Intel ICH5 (24D5) (vmix)
Available for use
Engine 5: 4/Intel ICH5 (24D5) (vmix)
Available for use
Engine 6: 5/Intel ICH5 (24D5)
Available for use
Input formats (0x00000410):
AFMT_S16_LE - 16 bit signed little endian
AFMT_AC3 - AC3 (Dolby Digital) encoded audio
Output formats (0x00000410):
AFMT_S16_LE - 16 bit signed little endian
AFMT_AC3 - AC3 (Dolby Digital) encoded audio
Device handle: PCI08501849-0000:00:1f.5-au01
Related mixer dev: 0
Sample rate source: 0
Preferred channel configuration: Not indicated
Supported number of channels (min - max): 2 - 6
Native sample rates (min - max): 48000 - 48000
HW Type: Not indicated.
Minimum latency: Not indicated


Nodes
/dev/dsp -> /dev/oss/oss_ich0/pcm0
/dev/dsp_in -> /dev/oss/oss_ich0/pcm0
/dev/dsp_out -> /dev/oss/oss_ich0/pcm0
/dev/dsp_ac3 -> /dev/oss/oss_ich0/pcm0
/dev/dsp_mmap -> /dev/oss/oss_ich0/pcm0
/dev/dsp_multich -> /dev/oss/oss_ich0/pcm0

lspci -v
...
00:1f.5 Multimedia audio controller: Intel Corporation 82801EB/ER (ICH5/ICH5R) AC'97 Audio Controller (rev 02)
Subsystem: ASRock Incorporation Device 0850
Flags: bus master, medium devsel, latency 0, IRQ 17
I/O ports at d800 [size=256]
I/O ports at dc00 [size=64]
Memory at febff800 (32-bit, non-prefetchable) [size=512]
Memory at febff400 (32-bit, non-prefetchable) [size=256]
Capabilities: <access denied>
Kernel driver in use: oss_ich
Kernel modules: snd-intel8x0

[cesium]

Hmm.. What happens if vmix is disabled? Also what if mixext.spkmode is set to FRONT?

[Boss32]

main@main-desktop ~ $ ossmix
Selected mixer 0/ICH AC97 Mixer (ALC850)
Known controls are:
vol [<leftvol>:<rightvol>] (currently 75:75)
pcm [<leftvol>:<rightvol>] (currently 82:82)
speaker <monovol> (currently 56)
line [<leftvol>:<rightvol>] (currently 66:66)
mic <monovol> (currently 77)
cd [<leftvol>:<rightvol>] (currently 75:75)
igain [<leftvol>:<rightvol>] (currently 62:62)
aux1 [<leftvol>:<rightvol>] (currently 32:32)
phone [<leftvol>:<rightvol>] (currently 53:53)
mono <monovol> (currently 75)
video [<leftvol>:<rightvol>] (currently 50:50)
rear [<leftvol>:<rightvol>] (currently 75:75)
center [<leftvol>:<rightvol>] (currently 75:75)
micboost ON|OFF (currently ON)
recsel.left <MIC|CD|VIDEO|AUX|LINE|STEREOMIX|MONOMIX|PHONE> (currently MIC)
recsel.right <MIC|CD|VIDEO|AUX|LINE|STEREOMIX|MONOMIX|PHONE> (currently MIC)
mixext.centervol [<leftvol>:<rightvol>] (currently 100:100)
mixext.rearvol [<leftvol>:<rightvol>] (currently 100:100)
mixext.sidevol [<leftvol>:<rightvol>] (currently 100:100)
mixext.rear2linejack ON|OFF (currently OFF)
mixext.center2micjack ON|OFF (currently OFF)
mixext.spkmode <FRONT|SPREAD> (currently FRONT)
mixext.mix-lfe2front ON|OFF (currently OFF)
mixext.mix-rear2front ON|OFF (currently OFF)
spdout.enable ON|OFF (currently OFF)
spdout.adc/dac ON|OFF (currently OFF)
spdout.pro <Consumer|Professional> (currently Consumer)
spdout.audio <AUDIO|DATA> (currently AUDIO)
spdout.copy ON|OFF (currently OFF)
spdout.pre-emph ON|OFF (currently OFF)
spdout.rate <48000|44100|32000> (currently 48000)
spdout.vbit ON|OFF (currently OFF)
spdin.enable ON|OFF (currently ON)
spdin.monitor ON|OFF (currently OFF)
spdin.pro <decimal value> (currently 0) (Read-only)
spdin.audio <decimal value> (currently 0) (Read-only)
spdin.copy <decimal value> (currently 0) (Read-only)
spdin.pre-emph <decimal value> (currently 0) (Read-only)
spdin.mode <decimal value> (currently 0) (Read-only)
spdin.category <decimal value> (currently 0) (Read-only)
spdin.genlevel <decimal value> (currently 0) (Read-only)
spdin.source <decimal value> (currently 0) (Read-only)
spdin.channel <decimal value> (currently 0) (Read-only)
spdin.rate <decimal value> (currently 44100) (Read-only)
spdin.clock <decimal value> (currently 0) (Read-only)
spdin.signal <decimal value> (currently 0) (Read-only)
spdin.vbit <decimal value> (currently 0) (Read-only)
vmix0-enable ON|OFF (currently OFF)
vmix0-rate <decimal value> (currently 48000) (Read-only)
vmix0-channels <Stereo|Multich> (currently Multich)
vmix0-src <Fast|High|OFF> (currently High)
vmix0-outvol <monovol> (currently 25.0 dB)
vmix0-invol <monovol> (currently 25.0 dB)
vmix0.pcm1 [<leftvol>:<rightvol>] (currently 25.0:25.0 dB)
vmix0.pcm2 [<leftvol>:<rightvol>] (currently 25.0:25.0 dB)
vmix0.pcm3 [<leftvol>:<rightvol>] (currently 25.0:25.0 dB)
vmix0.pcm4 [<leftvol>:<rightvol>] (currently 25.0:25.0 dB)

5.1 not work, stereo only

[cesium]

Hmm.. So you're using SPREAD setting for this? I think it's a bit naive (IIRC output is copied to all the other speakers. An expander can be more sophisticated).

A) Try getting this file and play it with ossplay. Does it sound fine? (e.g. with spread and vmix off).
B) Enable spread again, and turn off vmix. Is sound quality ok?