[PlanetCCRMA] Mulitple Jack audio interfaces (was Tascam US-122 audio problem)

Fernando Lopez-Lezcano nando@ccrma.Stanford.EDU
Wed Feb 23 23:14:00 2005

On Wed, 2005-02-23 at 16:54, Ben Cohen wrote:
> > If you are only correcting for clock accuracy and
> > using the same sample rate
> > (e.g. two soundcards running at 48K) then you only
> > need delete/insert a sample
> > every few 100,000 or million samples. Smooth it a
> > little and it shouldn't be too
> > bad cpu-wise.
> Wow. I did't think this would be possible without a
> lot of work. 

It _is_ not possible without a lot of work (IMHO). This issue surfaces 
often on lau and the jack lists. Once you start looking at all the
details that are needed to make it work, then it is not so easy.
Obviously the audience is always welcome to prove that wrong with
working code :-) It is not impossible, of course.

But I'm not aware of any existing, working software solution to this
problem (and I think it is becoming less and less of a problem as quite
cheap cards start coming with multichannel i/o). 

> It would be an very useful way of getting
> the most out of low end/consumer equipment. I know a
> lot of people who have an audio device on there
> motherboard and a PCI device too. This could allow for
> four track recording or 2 sets of stereo FX processing
> which would get some DJs I know very excited!
> I assumed that it wouldn't be in keeping with the
> opening statement on the Jack website and so I stopped
> looking ("JACK was designed from the ground up for
> professional audio work").

Well, it is...

Timo Sivula managed to get an "el cheapo" setup working but it involved
synchronizing (in hardware) several cheap cards so that they run from
the same crystal. 

-- Fernando