>BTW, can JACK handle several HW interface using different blocksizes >at a time (assuming sample frequencies are coherent) ?
multiple devices: we leave that to ALSA. we just open one ALSA PCM device, which may or may not correspond to a hardware audio interface. ALSA can handle a variety of these situations, but AFAIK, it does not handle sample clock drift and related issues. different blocksizes: hard to even define, really, but pretty much beside the point given that multiple devices are handled by ALSA. --p