PT11 Crackling Entire Time

Constant crackle the whole time I'm trying to mix. Played around in Playback engine and gets a little better or worse.



Headphones straight in. Only hardware is Ilok.



Any help would be much appreciated.



PT11.3.1

MacBook Pro (Retina, 15-inch, Late 2013)

Yosemite 10.10.2

Quad core 2 GHz Intel Core i7

8 GB 1600 MHz DDR3

Intel Iris Pro 1536 MB