I run Ubuntu 11.10 (32 bit) on a Dell Inspiron 9400. Per default, however, the multimedia buttons control a weird mix of Master, PCM and LFE settings that lead to a jump in volume on the first step and not much difference on subsequent ones. Also, the mix between front speakers and subwoofer is poor.
By playing around in the alsamixer my guess is that best results would be achieved by setting Master (that apparently controls front speakers) and LFE (the subwoofer) fixed and control only PCM (that seems to be the master volume).
Is there any clean way to configure this? Or is this the wrong approach to begin with?