Re: [LAU] JACK with many soundcards

From: Paul Davis <paul@email-addr-hidden>
Date: Mon Jul 28 2008 - 19:01:05 EEST

On Mon, 2008-07-28 at 17:51 +0200, Adrien DANIEL wrote:
> Thank you very much, that seems to come up to my expectations !
>
> I take advantage of this thread to explain my thoughts.
>
> I was thinking about, for instance, an electric guitar with a built-in
> ADC, that could be plugged in a computer via a USB (or Firewire)
> cable, the guitar being recognized as a 'snd-usb-audio' device under
> the system. With this view in mind, it might be useful to get many
> "digital" instruments like that, as well as a DAC, all available in a
> single JACK server.

JACK is not designed to work this way. it was designed around the
assumption that your instruments plug into some kind of audio interface
(not necessarily analog, it could be all digital). individual
instruments all showing up as distinct USB devices is really rather
outside of the design assumptions that JACK was started with. in
particular, there has long been a model within JACK that device
aggregation was the job of the OS audio services (ALSA, CoreAudio etc).

> Will JACK2 be able to handle this ? I mean, you run jack2_start, and
> all the available (and desired) peripherals appear in the connections.
> :)

its possible. i don't think this is part of the plan at present. a
future in which a USB hub is considered an audio patchbay, and audio
apps have to interrogate the USB bus to determine what is out there ...
well, its not inconceivable, but its not likely to take off, i think.

> I suppose that it raises many issues like synchronization between
> different physical peripherals. Handling many peripherals as separated
> devices might not be optimal compared to one single device with
> multiple inputs/outputs, as well. And actually I am not sure this idea
> is really essential... :)

not only is it essential, its really tending toward the silly. the
converters in those "USB guitars" are not really very good for the most
part, and besides a lot of people still strongly prefer mic-recorded
instruments. oh, and did i mention that a given USB bus will get totally
saturated with very few channels, so to do this usefully for a bunch of
performers you would need a lot of USB busses to connect to.

--p

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Received on Mon Jul 28 20:15:06 2008

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