Note that if Audio to buffer in Audacity’s Recording Preferences is the problem, reducing it below 100 ms is more likely to help than increasing it. Sometimes the playback will be fine for several seconds to 10s or 20s of seconds and then it would start popping again. When I play audio in Audacity I get random crackling and pops. I purchased the FireWire to Thunderbolt adapter and connected my Motu and it works fine with iTunes, QuickTime Player, Ableton Live 9, SoundCloud, etc. Motu states that my model is not compatible with El Capitan yet and they are working on new firmware but they also stated using FireWire would solve the problem. Recently I upgraded my OS to El Capitan and my Motu UltraLitemk3 Audio Interface (via USB2) failed to work. I have been using Audacity for some time now on my MacBook Pro.

My audio interface is set to 48kHz 24bit so I made sure the project rate was set to 48K. My buffer is set to the default 100ms, which I don’t think is the problem.

I tried nightly builds, old builds, latest released build and they all do the same. Unfortunately two things have changed… I upgraded to El Capitan OS and I changed from USB2 to FireWire via Thunderbolt adapter.

Quicktime player mac latest version