On 09/19/2010 06:17 AM, Jonathan E. Brickman wrote: > I was reading here: > > http://bpmdj.yellowcouch.org/jack.html > > and became intrigued. A few questions. I would love to be able to run > with (say) three ordinary USB2 audio-in ports plus my AudioTrak Prodigy > HD2. > > 1. Can different jackd instances, connect and talk to each other? If I > run four instances of Jackd and qjackctl under four different names, can > I connect them all? No. but you can connect multiple soundcards to one jackd instance using alsa_in and alsa_out. Note however, that alsa_in/out does resample (unless the soundcards involved are synchronized by word-clock) and you loose sound-quality. (FWIW you can use netjack to connect two or more jackd instances - but then you still need alsa_in/out because the netjack slaves do not connect to an underlying audio-device but connect to the master-jack.) > 2. In the example at the web page linked above, an "ALSA multi" device > is shown, combining multiple devices into one ALSA virtual device. If > memory and CPU is not an issue, will doing this with one Jackd instance > work better than four interconnected Jackd instances? It seems to me > that this would require a "lowest common denominator" approach to > latency-related settings, and combining PCI and USB strikes me as > possibly troublesome because of the very different needs involved. > > J.E.B. AFAIK alsa-multi devices only makes sense for soundcards that can be chained. It is possible to combine different devices on ALSA level but you'll most likely get a mess: Different latencies, buffer-sizes etc and experience drop-outs if the cards are not synchronized. YMMV. It may not matter to you if you use the 2nd soundcard only for telephoning or some similar task where you don't care.. but your time is spend better buying a decent soundcard with enough I/O :) best, robin _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
