Distorted Playback Only When Using Interface With Audacity

Okay, I’ve got a problem I can’t figure out.

Playback in Audacity comes out extremely distorted, but only when I’m listening through my interface, and only Audacity output is distorted - all other output works fine. Listening to anything else Garageband, iTunes, YouTube, etc through the interface is working perfectly fine. When not using the interface, playback in Audacity has no distortion at all and sounds fine. It is only the combination of interface and Audacity that’s creating a problem, and I’m stumped. I’ve been using this program and interface together for years without issue.

The comptuer is a 2011 MacBook Pro and I’m running OSX 10.6.8. I’m using Audacity 2.0.6. The interface is an Alesis iO2 Express.

I don’t understand why the problem would only occur with the specific combination of the two. If it was an interface problem, wouldn’t everything sound distorted? But everything else sounds perfect through it except for Audacity output. If it was an app problem, wouldn’t the output from Audacity be distorted coming from the laptop speakers or headphones plugged directly into the laptop as well?

I can literally listen to a wav file and it sounds perfect through iTunes or Finder, then load the same wav into Audacity and it sounds awful (but again, only through the interface - if I play the same wav through Audacity via the computer’s speakers or direct out, it sounds fine).

Any ideas? Thanks.

This is rough because you can’t post a sample of the distortion. Can you post samples from the Personal Recorder on your cellphone? Post five seconds of clear work and then another five second file of the distortion. Listen to the files to make sure they sound like you want.



Have you tried the obvious solutions first? Set Audacity project rate bottom left to 44100 Hz. Open /Applications/Utilities/Audio MIDI Setup, click the Output side and set the Alesis to 44100.0 Hz. If the Alesis default is some other rate, use that rate in Audacity and Audio MIDI Setup. Look at the Alesis manual for help with sample rates.

Try it just with one WAV in the project, no other tracks. If there is a song in the top track that has white space at the start, the songs undereath may crackle. That should be fixed in the next 2.1.0 version of Audacity.

It’s also possible that reducing Audio to buffer in Audacity’s Recording Preferences may help (it affects playback too). Don’t take it too low or it may mess up playback of the built-in audio device. The default buffer is 100 ms, if you need to go back to the original setting.