CPU overload with 1 virtual instrument when sample rate >

[johnnyfantastic]

Hi. I've got Logic 9, an 8 core Mac, and 8GB of RAM running OS X 10.6.7. Logic is running in 32 bit mode.

I've also got a Lynx Aurora + AES16e for AD/DA conversion

 

When I change the sample rate of my project to anything other than 44.1KHz and play 1 virtual instrument my CPU spikes with any more than 5 notes playing at the same time. Related I think, when I throw a multimeter on an any track with a sample rate > 44.1KHz my CPU also spikes and I hear pops/clicks.

 

Recording live audio seems fine, for example, I can record an instrument at 96KHz/24bit with no CPU usage to speak of.

 

I've got a beefy system, and the CPU literally spikes with 1 virtual instrument when the sample rate isn't 44.1KHz. When the sample rate is 44.1KHz I can run 30 instruments with no trouble...

 

Any ideas? Thanks for your help

[involver]

Read this to understand how Logic handles multi-core use.

 

http://support.apple.com/kb/HT3161

[johnnyfantastic]

Thanks - I think (hope) I have a more fundamental problem than that.

 

If I start a new project, add a Software Instrument and set it to, for example, a Yamaha piano at 44.1KHz I'm fine, I can play anything via MIDI controller with no problems. If I increase to 48KHz, all of a sudden my CPU spikes to the point where I can't play anything via MIDI.

 

There are plugins involved with the Software Instrument, yes, but surely I should be able to add a piano to an empty project at 48KHz and track it via MIDI controller without my CPU overloading. And to clarify, when I say overloading, I mean 100% CPU usage so an error message pops up and the tracking pauses, sound clicks and pops.

 

And final point of clarification, the sample rates in Logic, the Audio/Midi Setup window, my Lynx Mixer and the Aurora are all in sync, i.e. 48KHz.

 

I appreciate your help!

[involver]

Just for trouble-shooting purposes, try using the built-in audio interface. Does it still have this problem?