[LAD] Multiple JACK servers connected in one host?

Len Ovens len at ovenwerks.net
Fri Mar 11 21:17:36 UTC 2016


On Fri, 11 Mar 2016, Jonathan Brickman wrote:

> Nope, I don't want to switch engines.  Everything runs at once, and
> runs very well by the way.  I just want to take more advantage of
> what I have, by running some things asynchronously, exactly the way
> some are already doing using multiple motherboards.

Ok, I am not seeing any sign of this at all. I am obviously not echoing 
your setup exactly... in fact my setup should be more prone forcing 
everything to one core. I have 4 cores. I started just adding synths... 
examples include yoshimi because you mention it, setbfree, calf fluid, 
hexter, synthv1. I have them all set up in separate chains either inside a 
carla box or just jack strings. They feed into one nonmixer, some of the 
channels have aux to reverb. All of the synths are fed from the same midi 
input.

Jack dsp goes up to about 10.5% max, The four cores all bounce around from 
about 7% to 15%. The important word here is all. There is not one that is 
higher than the rest.

Now true, I am running only 6 synths, but I would expect to start to see 
some indication of uneven load by now if there was a problem. Three times 
more synths does not look like a problem. Is there one particular 
application you have that just takes a big chunk of dsp/cpu?

(Yoshimi does not like changes in buffer size BTW)
(nonmixer does not have solo/pfl/afl or mute groups, so listening to just 
one channel is more work than I like)

The Carla boxes seem to have been the biggest CPU users here. (not 
surprising really and may reflect the plugins more than the host anyway)

I notice you use velocity to adjust levels. In the case of some synths 
that may not make a lot of difference, but many of them have a timbre 
change with velocity. I suspect the mutes in nonmixer could be controlled 
by midi/osc which would allow using a change of output level for even 
timbre. On the other hand maybe a synth alone should be softer so when 
mixed with another it is still within range. This would be closer to the 
natural (acoustic) mix. No worries though, it is all artistic preferences 
after all. Maybe in an acoustic situation a player would hold back when 
playing with others and not when soloing...

--
Len Ovens
www.ovenwerks.net


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