[LAD] 9 soundcards ?

[Dominique Michel]

Le Mon, 11 Nov 2019 20:26:47 +0100,
lacuna_ at gmx.net a écrit :

>  
> Hello,
>  
>  
>  I'd like to run up to nine soundcards with Jack.
> 
> Eight times Expert Sleepers ES-8 via USB
> and one RME Madi HDSPe card on a PCIe slot.
> 
> In Linux at 96 kilobauds.
> 
> I read here
> https://jackaudio.org/faq/multiple_devices.html
> about clocking issues as each card is run by it's own clock.
> 
> Will the asynchronously clocked streams be handled and merged by Jack
> or is this an ongoing issue?

It is an hardware issue. Each card have its own hardware clock, they
are some kind of quartz oscillators often associated with PLL
circuitry. They are implemented into the silicon of the cards and it is
nothing JACK can do about this.

The only solution would be to use a Master clock, which is to use the
clock of one card as clock for all the cards. That can only be done at
the hardware level. In your case, that imply to modify the hardware of
the cards, which, with 8 USB of one brand and 1 PCI card of another
brand would be rather complicated, if possible. Even if we consider
only the 8 USB cards of the same brand, it is more than doubtful the
clock of one of these cards would be powerful enough to be able to
drive the 8 cards. Which imply this would not be a trivial modification.

Dominique


-- 
If you have a problem and you are not doing anything to fix it, you are
at the heart of the problem.