hello i had quite similar experiences with usb hubs and usb soundcards and also midi interfaces the usb sounddevice for instance, wanst working over a unpowered usb hub, and of course doing his job when connected directly. and some interfaces may not work correctly like described above. for instance the usb midisport 2x2. i coulnd get it working to provide midi signal out into old analog syntesizers ( i guess they are more sensitive or have more powerconsumption, i dont know, on the midi site ). i had to route it through powered midi i/o ports to get it working. so i gave that interface away. i dont know if this has anything todo with alsa, i dont think so. best m ----- End forwarded message -----