https://www.macnn.com/articles/15/10/05/teething.problems.abound.like.any.new.major.os.release.130699/
Music mavens might have migration issues
While we're not flooded with problems, Core Audio has changed a lot, and so has the kernel. So, devices like the M-Audio (now Avid) Fast Track C600 recording interface, and Avid Mbox 3 audio interface no longer function. Other older, but not strictly "legacy" audio interface external devices have stopped working under El Capitan with provided drivers -- some companies note that their devices are full Core Audio devices, and the solution is to totally remove the company-provided software!
Logic Pro X is seeing random audio cuts, as well as distortion under El Capitan for some users. Native Instruments is recommending that customers wait on the update, because of incompatibility issues with Komplete, Maschine, and Traktor. Developers of Cubase and Nuendo Steinberg are advising users to wait to upgrade. Finale 2014 won't be updated to support El Capitan until the middle of November. Apogee's Ensemble won't be updated for El Capitan at all, because the FireWire Core Audio driver has been depreciated. Many third-party plugins no longer function (such as iZotope's AU plugins), or have complex workarounds.
So, if you rely on OS X for audio production, you're best off to wait. In some music production cases, maybe never upgrading at all -- at least until you swap out your old Firewire-based stuff for Thunderbolt or USB 3.0 -- is the best choice.
Music mavens might have migration issues
While we're not flooded with problems, Core Audio has changed a lot, and so has the kernel. So, devices like the M-Audio (now Avid) Fast Track C600 recording interface, and Avid Mbox 3 audio interface no longer function. Other older, but not strictly "legacy" audio interface external devices have stopped working under El Capitan with provided drivers -- some companies note that their devices are full Core Audio devices, and the solution is to totally remove the company-provided software!
Logic Pro X is seeing random audio cuts, as well as distortion under El Capitan for some users. Native Instruments is recommending that customers wait on the update, because of incompatibility issues with Komplete, Maschine, and Traktor. Developers of Cubase and Nuendo Steinberg are advising users to wait to upgrade. Finale 2014 won't be updated to support El Capitan until the middle of November. Apogee's Ensemble won't be updated for El Capitan at all, because the FireWire Core Audio driver has been depreciated. Many third-party plugins no longer function (such as iZotope's AU plugins), or have complex workarounds.
So, if you rely on OS X for audio production, you're best off to wait. In some music production cases, maybe never upgrading at all -- at least until you swap out your old Firewire-based stuff for Thunderbolt or USB 3.0 -- is the best choice.