EXS 24 Logic Sampler Users Group

Dave Howard wrote:
> Can anyone answer this:
>
> Apparently multiple instance of the EXS don't use any more CPU than
> one....correct?

As long as they are a) not playing anything and b) their tracks are not
selected in your arrange, yes.
As soon as you select a virtual instrument track in the arrange (no matter
if there are sequences or not) it will start using a bit of CPU as it has to
be "realtime-enabled".

> Am I correct in assuming that the polyphony of the instances DOES affect
CPU
> usage?

I didn't noticee any difference on my machine, playing the same sequence
(like 3 note chords without any overlapping notes and/or release times)
through an 8 voice patch and through the same patch with the voices raised
to 64.

> And is it dynamic? In other word, 16 instances with maximum polyphony
won't
> increase CPU load, but as the number of notes/voices being used increases
so
> does the CPU load.....?

I don't quite understand this question...
More voices being played = more CPU load. As said above as long as there's
not as much voices being played as the polyphony setting allows I can't
notice amy difference (well, maybe I should check that back under real high
CPU load).

> Is there any benefit to limiting polyphony in the instances of the EXS?

Yes. Here's an example: Let's assume you have a pad sound with a fairly long
release time. Now play some chords changing faster than your release time
(maybe you could even play 3 or 4 chords before the release is "finished").
Let's now assume you're playing 4 part voicing with 2 zones per each voice =
8 voices in total. Now play the second voicing before the first chord is
completely released = 16 voices. 3rd chord = 24 voices.
This will eventually result in pretty much voices being used = high CPU
load.
But of course it might not be necessary to have all the releasing voices
being still present on the 3rd chord (maybe not even on the second), so you
could just limit your polyphony to 16 voices (or maybe even to 8). This
would make sure that at the time you play your 3rd chord everything
"redundant" from the 1st chord will be "stolen".
Especially when dealing with patches only using a small amount of "vertical"
zones (in that case the EXS has to do a lot of pitch calculation which still
seems to be one of the most CPU hungry things) this method could save up
quite some CPU horsepower.

Regards,
Sascha