Re: [Alsa-user] how to convert stereo-> mono signal during record

[James S. <Sha...@ea...>]

On Thu, 28 Aug 2008 17:03:44 +0200
brunal <bru...@gm...> wrote:

> I have to precise that I'm using a M-Audio fatst track pro sound  
> card, which works fine if I only record stereo files.

Is there some reason the application doesn't do mono?  Almost all I've seen allow you to record only one track.  Even on my MCP61, or my Mobile Pre.  Which are stereo devices.  You could look at audacity to see how it does it.  Although it might be difficult to find being a multiplatform application.  Ardour lets you do it, but it's using jack.

At a minimum you should be able to split the track out after the fact.

$ sox -c 2 stereo.wav -c 1 mono.wav avg -l

Maybe not useful for you if you need to do realtime continous recording.  Or something like voice recognition.  But arecord allows mono recording from a stereo device.  Perhaps look at it's source for an example.  My Korg MR-1000 is a stereo device that only records in stereo.  But it's a stereo field recorder, that afaik doesn't run linux.

HTH