Poor sound quality with snd_via8233

[Ariff Abdullah]

On Sat, 18 Mar 2006 14:58:13 +0100
Niklas Sorensson <nik at cs.chalmers.se> wrote:
> Hello,
> 
> I experience constant poor sound quality with the snd_8233 driver,
> ie not  interruptions due to temporary load or anything like that,
> but constant  distortion. I've been able to live with it because its
> good enough to use for  Skype, but I really would like to be able to
> listen to music as well.
> 
> I've searched mailing lists and googled, but couldn't find any
> problem  description that fits mine.
> 
> I'm running current, on an ASUS K8V Deluxe board. My kernel config
> and details  about the sound setup is attached.
> 
> Any advice on how to improve the situation is appreciated
> 
> 

[..]

> apa# dmesg | grep ^pcm 
> pcm0: <VIA VT8237> port 0xc800-0xc8ff irq 22 at device 17.5 on pci0
> pcm0: <Analog Devices AD1980 AC97 Codec>
> pcm0: <VIA DXS Disabled: DXS 0 / SGD 1 / REC 1>
I suggest you remove hint.pcm.0.via_dxs_disabled from
/boot/device.hints.


> apa# /usr/sbin/mixer
> Mixer vol      is currently set to 100:100
> Mixer pcm      is currently set to 100:100
> Mixer line     is currently set to 100:100
> Mixer mic      is currently set to 100:100
> Mixer cd       is currently set to 100:100
> Mixer rec      is currently set to 100:100
> Mixer igain    is currently set to 100:100
> Mixer ogain    is currently set to  10:10
> Mixer line1    is currently set to  75:75
> Mixer phin     is currently set to   0:0
> Mixer phout    is currently set to   0:0
> Recording source: mic
>
Reduce those "100" to "85", or less. You're overdriving it too much,
hence, the constant distortion. If you have amplified speaker, use the
volume knob there.

Report (and partially from my experiences) indicate that using
SCHED_ULE can give better audio/multimedia performance. Perhaps you
want to give it a try.


--
Ariff Abdullah
FreeBSD
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