[linux-audio-user] aplay, plughw, alsamixer question

[fpirrone]

Mark Knecht wrote:

>No responses here also?????
>
>  
>
>>-----Original Message-----
>>From: linux-audio-user-admin at music.columbia.edu
>>[mailto:linux-audio-user-admin at music.columbia.edu]On Behalf Of Mark
>>Knecht
>>Sent: Friday, July 25, 2003 7:42 AM
>>To: Linux-Audio-User
>>Subject: [linux-audio-user] aplay, plughw, alsamixer question
>>
>>
>>Hi,
>>   Hi. I asked this question on Alsa-Dev yesterday, but 17 hours later got
>>no answers. Excuse me to those that subscribe to both lists.
>>
>>   This info is to help me do more debug work on a new HDSP 9652 driver
>>version that I am helping to test.
>>
>>   Should the volume levels I hear when using the command
>>
>>aplay -Dplughw:0 -r 44100 data/wave/seque~10.wav
>>
>>be controlled by alsamixer?
>>
>>The volumes for alsaplayer are being controlled by alsamixer, but
>>this aplay
>>command is not, at least right now on a new driver I'm using.
>>
>>   Also, on a multichannel card, how do I direct the above aplay
>>command to
>>a specific channel? I am finding that with this new driver the audio is
>>appearing on ALL channels on the card, even for a mono wave file. I think
>>this is a bug, but I'm not sure.
>>
>>   If there's an explanation fit for a simpleton like me about the
>>difference between plughw and hw and when to use one vs. the other, please
>>point me there so I can learn. I have read a bit on the Alsa site about
>>plughw talking directly to the kernel, but beyond that I have not
>>discovered
>>any documentation yet.
>>
>>   Thanks in advance.
>>
>>Cheers,
>>Mark
>>
Mark,

I don't have any experiences with your hardware and didn't think my 
reply would be of much use to you, but running the exact command you 
post on my cs4236 system produces sound that is under control of 
alsamixer, as does -Dhw:0, so that suggests to me that aplay is directly 
affected by the settings in the mixer.  

Now, some cards do not have a mixer so they should not behave this way, 
as I assume would be the case if there were something wrong with the 
driver for a card that does have a mixer.  In either event I would not 
expect to see controls in amixer or the gamix graphical interface.  If 
you see them and they have no effect that sounds like a malfunction.

Couldn't find any answer to your channel question.  My system does not 
seem to provide a relevant option to explore this further.  I fooled 
around with -c and -I options but could draw no useful conclusions.

Frank