[LAU] JACK with many soundcards

[Arnold Krille]

Am Montag, 28. Juli 2008 schrieb Adrien DANIEL:
> I am wondering how to use JACK with more than one soundcard. For
> instance, what if I want to get one of the inputs of my soundcard #1,
> process it with a JACK program, and finally send it to one of the
> outputs of my soundcard #2 ?
> Should I launch several JACK deamons ? If so, would I be able to
> interconnect them ?

Apart from the fact that there are ways of doing this in software (with all 
the latency and uncertainty that arises there), you should *please* look at 
the archives of this list and find out why it is nearly impossible to do what 
you are thinking of.
In short: You definitely need to get the clocks of the converters in sync. And 
you should also get the interrupts in sync.
This first part is possible with some soundcards (in the higher price-range) 
and with firewire-soundcards (as long as they are supported by 
freebob/ffado). The second part involves kernel-hacking, is optional but 
should improve the stability.

In clear words: In the price-range where people think about syncing two cheap 
soundcards to safe money instead of buying a higher quality device, this is 
not possible without jumping through a lot of hoops. In the price-range where 
this is easier, it is not used to sync two devices to get a total of up to 8 
channels (for example) but used to get a total channel count of >=16...

Have fun,

Arnold
-- 
visit http://www.arnoldarts.de/
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