USB > DAC distortion [SOLVED]

I’m getting distortion at unpredictable times (but now pretty much within seconds) on playback through both USB ports > DAC on my late-2011 MacBook Pro:

Mac OS X Lion 10.7.5
Intel i7 at 2.8 GHz
4 GB 1333 MHz DDR3

Sometimes it distorts and fades to silence, and at other times it just distorts. If I stop and restart it may play through or may distort quickly. This does not happen on the built-in 1/8" output. I have a new Audioengine D1 DAC. Used it earlier in the week through a pair of Audioengine 2 with Dayton 8" sub… Sounded nice. During that first listening session, I started hearing distortion on playback only from my four-track Audacity .aup files (24/44.1). I am saving and running files from a WD 3TB drive.

Fix attempts so far:

Exchanged the DAC with another new one.
Updated Audacity from 2.1 to 2.1.1.
Reset PRAM.
Tried both USB ports.

I did use a NuForce DAC in the past with no problems.

Anyone ever heard of this problem?

Create a set of test files at 16-bit, 44100. Do they play OK?


Have you tried reducing “Audio to buffer” at Audacity > Preferences…, Playback section?


Increasing the buffer did indeed solve the problem. Thank you very much for your help.