I suppose this would be better on linux-audio list, but I'm not a member there and I thought I'd see if any one here knows first.
I just bought an M-Audio Quattro that I thought, for some reason, would work fine in Linux. After compiling a new kernel (2.6.6), applying the third patch from Allen Stern on the linux-audio list (I heard the first two of the three were integrated into 2.6.6), loading snd-usb-audio, and using the .asoundrc from alsa-project.org's ez-usb (heh, ez... right) page, I can finally get audio out of the card. I don't have any idea what sample rate or bit depth it's running at, because I can't get Jack to work yet, and I may be frying all its ever-so-delicate innards as we speak.
The problem now is that there doesn't seem to be any way to change the volume. When I configure the ALSA output in XMMS (I'll get around to the issues I'm having with PD when I've got this part figured out) I have two choices for the interface, Quattro and Quattro #1. If I select Quattro the volume is a good, loud level that doesn't change. When I select Quattro #1 the volume is barely audible and unchangable. By unchangeable I mean that the gnome-volume control has a tab for usb-audio with no sliders, alsamixer returns 'no mixer elems found', and XMMS's volume control doesn't do anything. In windows the system volume control is frozen but all the software volume controls work fine.
Any way, just thought I'd take a shot in the dark, as I figure someone else on the pd-list should have run accross this little MAudio beastie in their travels and might have some tips for getting it fully operational.
Thanks, Ian Smith-Heisters