sound distorted everywhere in fc4

[roskoo]

config PIII 600,256mo sdram133,bios ami,soundcard aureal au8810. Clean standard install of fc4 (the similar install options like my previous fc1,2,3...) with gnome+kde, firewall off or on ,SEL off or on (same issue), upgrade to kernel 2.6.12-1.1398,sound server=esd ou not, I use gnome :
the sound is distorted under all multi-media readers applications (from totem to xine): slightly accelerated by jerks, with crackings and very small cracklings from time to time, I tried many options but can't escape this "buggy sound" - I made the differents upgrades (kernel,alsa...). the driver for the aureal au8810 was included in alsa since kernel 2.6 and I get the correct sound from fc1 to fc3 (this one upgrade with differents kernel)
I try alsa oss arts esd etc but no way
what I can notice, is that in multimedia systems selector (desktop preferences) the audio defaut source input 'alsa' gave me this error 'Failed to construct test pipeline for 'ALSA - Advanced Linux Sound Architecture'
so I need your precious lights this time, because music is essential for me.
sorry for my english

[ryuheixys]

did you check to see if your mixer for various things are not turned up? (for me turning up the CD volume sometimes gives me distortions)
If you did, did you try not using a sound server? there is an option to directly pipe to alsa. If your card doesn't support hardware mixing look up something called "dmix" on the forum. good luck

[roskoo]

thanks ryuheixys for your quick answer
I try to modify some differents things in the mixer (turning up the CD volume for example) with no succes,
the aureal card driver support hardware mixing and it was nice in previous version of fedora.

[roskoo]

just a few hours ago my "fc4 everywhere distorted sound" disappear after a bios modification (ami 2001) apm =disabled [B]- in fact I was looking to an acpi=off solution, fighting an other issue- usb device freezing my fc4 desktop -but dont find this acpi choice in my old bios - acpi=off in grub.conf doesn't change anything to the sound and usb pb - only apm disabled in bios restore the sound .
but so, now my pc only halt when I shutdown and I can't get the power off - is there any solution to power off with apm disabled in the bios?

[multescugeorge@]

so the command:
poweroff
doesn't stop the computer? Strange...

[roskoo]

poweroff give:
shutdown: hda
power down