How to play audio on stereo device

[Jin Guojun[VFF]]

I have a stereo sound card, and audio applications only can use one 
channel at a time.

By default, sound goes out to the Rear port (pcm0). If set 
hw.snd.default_unit to 1, then sound only goes to the Front port (pcm1).

Is anyway to configure system to use both front and rear audio channels?

-Jin


cat /dev/sndstat

pcm0: <Realtek ALC887 (Rear Analog)> (play/rec) default
pcm1: <Realtek ALC887 (Front Analog)> (play/rec)
pcm2: <Realtek ALC887 (Internal Digital)> (play)
pcm3: <USB audio> (play/rec)