Logic Pro 9 Logic forces processing of all outputs from multi-output ins "to a single core".


New Member
Logic forces processing of all outputs from multi-output ins "to a single core".
This is a real drag when you set up several multi instruments in Logic in a multi core mac pro.
In my case I created a big orquestral template in Logic using about 13 multi instruments loaded with each corresponding Vienna Ensemble pros connected overlan to a Vienna Ensemble server inside the same mac pro. In Logics mixer, the aux channels from the multi instrumetns are the audio returns from the Ve pro server where the sound libraries are loaded, outside of Logic.
I notice that in Logic, using these auxes routed to buses in the mixer, forces all the channels to a single core, witch ends overloading the system and making it unpractical. But If you eliminate all the auxes from the multis and route all the channels outs to outs 1 and 2 then Logic engines uses evenly all the cores. Very Extrange!.
thsi seems to be a flaws in Logics audio engine, a real drag for anyone that wants to create and use multinstruments with Vienna Ensemble.

Tomás San Miguel

Mac Pro 2 x 2.93 Ghz 6 core intel Xeon
32 Gb RAM
OSX Snow Leopard 10.6.4
SATA 64 bit cache internal RAID Drives holding the Libraries.
SATA external Drives holding the sessions and video.
VEpro v. 7349
VI pro v. 7349
Logic pro 9.1.3 (64bits)
Sibelius 6.2

I can confirm that Logic uses 1 core for all live inputs (what the returns from VEPro would be).

I created a template using 2 instances of VEPro, each having 3 projects, and each project having between 3 and 12 instruments loaded, with a total of about 40 stereo returns going from the VEPro servers.

There are also about 50 audio tracks with input audio enabled, so I'm talking about 90 live inputs plus we use 1 VI at the same time, and we are not having any issues. this is with the same speed CPU (we have a 12 core rather than a 6 core, but the 1 cpu issue would be the same thing).

So, either your system is buggered somehow, or you are running a very small buffer (we run a 256 so we don't have core overload issues).

All that said, what is your I/O buffer size?


New Member
I use 256 buffer. But it has nothing to do with the problem I describe. The tech people from Vienna instruments confirmed to me that Logic pro is not processing the auxes from the multinstruments correctly and evenly to all the cores instead just to one. I can send you pictures of the tests I did using Ve-pros oveland versus individual VI-pros in logic, the core behavior in both cases is shocking.
How much ram then... the reason i ask is, you would think that with the same CPU (only doubled) that I would see the same issue, but I am not.