[linux-audio-user] Patch one channel to both channels in ALSA?

[Peter Clarke]

Is there a neat software solution for patching, say, the 
left channel of PCM output to both channels of the line 
output of my soundcard in ALSA?

I need this because I've just installed a TV card, which 
works great except that the dual language function doesn't 
seem to be supported.  So I get English in one speaker and 
Chinese in the other.  I'd rather have the same in both.

I thought of doing it with the JACK patchbay, but the TV 
output unfortunately doesn't show up in JACK.

Thanks for any help,

Peter C