[alsa-devel] Surround problems with cs46xx

Vasilis Manοlopoulos vmanolop at gmail.com
Wed Jun 20 06:49:01 CEST 2007

Thanks for the reply Takashi.
I don't think that this is hardware problem, cause in windows XP, using 
the drivers by the manufacturer Hercules, the sound is fine. About the 
test you mentioned, I 'll check it when I find free time on weekend and 
I 'll let you know the results. I hope you could provide me some further 
help then. Unfortunately I am new in linux & sound issues, so creating a 
6 channel wav file and the whole procedure is a bit difficult to me and 
it's better to deal with it in the weekend!!


O/H Takashi Iwai έγραψε:
> At Sat, 16 Jun 2007 16:56:53 +0300,
> Vasilis Manwlopoulos wrote:
>> Hi,
>> Sorry for bothering the list again, but I have major problems with the 
>> surround 5.1 sound. I have manually compiled/installed th latest 
>> alsa-1.0.14 drivers but nothing improved. I am using Ubuntu 7.04 and my 
>> soundcard is  the Hercules Fortissimo III. This is, as far as I know by 
>> reading on Internet, supported by the module snd-cs46xx in ALSA. I have 
>> enabled the surround sound by creating the following .asoundrc file.
>> pcm.!default {
>>     type plug
>>     slave.pcm "surround51"
>>     slave.channels 6
>>     route_policy duplicate
>> }
>> The problem is that sound pauses whenever I try to do something "heavy" 
>> such as opening a new firefox window or generally another app. Also, 
>> there are delays and echo between the front and the rear speakers from 
>> time to time. I think that the problem is that, this alsa setup(meaning 
>> surround5.1 and the specific soundcard) places a heavy load on the cpu. 
>> There are 99% cpu usage times when the only thing active is a player 
>> playing a "normal bitrate" mp3. When I delete the .asoundrc file and I 
>> switch to default stereo sound using only the 2 front speakers the 
>> problems disappear.
>> Can anyone suggest anything about this?
> First, try to investigate whether it's a problem of surround51
> implementation or rather the "default" definition above.
> For example, prepare a 6-channel WAV file, and play directly with
> surround51 PCM.
> But, from the symptom, I'm afraid it's rather a hardware problem.
> The cs46xx uses three stereo streams for 5.1 output, and they are not
> strictly synchronized.  And, debugging cs46xx driver is really a
> nightmare...
> Takashi

More information about the Alsa-devel mailing list