cannot adjust audio balance with OSS on old iBook

[Frank Murphy <murphyf+deb-ppc@f-m.fm>]

I just noticed that I can't adjust the audio balance on my iBook. When I boot 
into OS 9, I can adjust it, so it seems to be a Linux problem. When I adjust 
the balance with aumix or xmms to be stronger on the left, the volume 
decreases, and it increases when I strengthen it on the right. When I listen 
to music, it is stereo. It's just the balance that won't work.

Others seeing this? Any ideas where this problem might lie? Because it happens 
in two audio apps, I imagine it's a lower-level problem. Anyone seeing the 
same thing with ALSA?

Frank