[linux-audio-user] bad sound quality (under a non-libre OS good)

I am installin Debian GNU/Linux on a Sony PCG-C1MV notebook computer. The owner of this computer is very picky aboud audio quality. I cannot make it work so the sound quality would be as good as in some non-libre operating system, which Sony has installed on it. I am playing exactly the same sound wav file, and under Debian GNU/Linux the audio quality is much worst than under the non-libre OS. The sound card is a PCI card like this: 00:06.0 Multimedia audio controller: ALi Corporation M5451 PCI AC-Link Controller Audio Device (rev 02) Subsystem: Sony Corporation: Unknown device 80ec Flags: bus master, medium devsel, latency 64, IRQ 9 I/O ports at 1800 [size=256] Memory at e8100000 (32-bit, non-prefetchable) [size=4K] Capabilities: [dc] Power Management version 2 I am using ALSA with the snd_ali5451 driver, but I also tried Knoppix and Gnoppix, (which autodetects and installs the trident OSS driver) and the problem is more or less the same, maybe a little better, but maybe not, hard to tell. I must say that for me the difference is very tiny, and I would not even notice that something is wrong, and I can only notice that there is a difference if I play on one OS and the immidiately reboot to Debian and listen to the same file. Otherwise I simply forget that it should be any better. The bad quality doesn't look like any extra noise, it looks more like some kind of distortion. It doesn't depend on video usage, moving windows, etc. Just in case, the video card is: 00:0c.0 VGA compatible controller: ATI Technologies Inc Radeon Mobility M6 LY (prog-if 00 [VGA]) Subsystem: Sony Corporation: Unknown device 80ec Flags: stepping, medium devsel, IRQ 9 Memory at f0000000 (32-bit, prefetchable) [size=128M] I/O ports at 2800 [size=256] Memory at e8110000 (32-bit, non-prefetchable) [size=64K] Expansion ROM at <unassigned> [disabled] [size=128K] Capabilities: [50] Power Management version 2 The card doesn't use DMA: venezia:~# cat /proc/dma 4: cascade venezia:~# The same under Knoppix. Also while playing a sound file. I've read the Audio-Quality-HOWTO for Linux at http://www.linuxdj.com/audio/quality/ but it didn't help. I've tried booting with the no-hlt option, no difference. I use the 2.6.0-2 kernel from Debian. What to do to make the audio quality as good as in the non-libre OS? -- Miernik ________________________ jabber:miernik@amessage.info ___________________/__ tel: +48608233394 __/ mailto:miernik@ctnet.pl Learn about crime done by George W. Bush in Iraq, and related to 9/11 http://www.whatreallyhappened.com/