All of my Logic X soft synths are crackling and popping since I upgraded the OS to Yosemite from Mavericks.

What audio interface are you using and did you check if there were compatible drivers for it, before you upgraded to Yosemite?

if it is not that then...

If you have the latest drivers and they are supposed to work in Yosemite or If you don't have an audio interface , do you have an Audio Router installed on your Mac like, for example, Jack or Soundflower? If so, those are likely to be the cause of the issue..... Uninstall them and test....

Lee,

Actually Im running 10.10.3 and LPX 10.1.1 here on two of my testbed systems and Im having no issues with crackling or whatever else with Software Instruments.... which is normally a sign of system overload... (given your audio tracks are fine)

So...

When you said it was Logic's SI's.. did you mean the built in ones or third party plugins (or both)?

What's Logic's CPU meter showing when this happens?

subsequently this is captured when bouncing to audio.

This is particularly strange that it would render to audio... as that indicates it's actual audio crackling rather than CPU/ Processing noise... which leads me to think that something else is going on here.. Maybe an FX plugin on the output or an aux being used?

As a quick troubleshooting test...

Assuming you have turned on all of LPX's Advanced Tools under Prefs (and if not you should!)

If you start a new project, with the Open Library checkbox unchecked...

add one Software Instrument track.. Choose one of Logic's built in plugins via the Instrument button in the track strip... choose a preset from inside the plugin... and then test.. do you still get this issue?

Ah.. Ok.. That makes sense.. Some audio drivers (or a combination of certain ones) just don't work well together when part of an aggregate device unfortunately. You may have come across one such combination/driver..

So, it may not be solely a Logic X issue...?

Indeed. This would then be a OS X (CoreAudio) and/or Driver problem.....

Either way, LPX would be declared "Not Guilty M'lud...."

🙂

Cheers..

Nigel

What I would do in your case, (may not work) is delete/destroy the current Aggregate device and rebuild it. If you left your audio interface(s) hooked up when upgrading it's possible for I/O software-hardware to become corrupted. For instance, some MOTU devices had to be reset to factory defaults after upgrading the OS with the unit hooked up (firewire) and on.

I would powerdown/power up your audio interfaces as well.

On the other hand, it can be the Yosemite upgrade. OS upgrades often change OSX USB/Firewire/ThunderB drivers

Lee@BMP wrote:

I just realised that this new OS doesn't require an Aggregate device to use two different units...

Problem solved!

Logic has been able to use separate Input and Output devices since Logic-9, on any operating system that supports the application!