sound quality problem - skipping

The sound from my 27in Thunderbolt display has deteriorated significantly. I use this display with a MacBook Air running Yosemite. It sounds fine when i launch, but soon it starts to degrade to a skipping/computer sound. If i change the sound in my computer's settings to come from the Internal Speakers of my computer, the sound is fine. then if i switch back to have sound come from 'Display Audio' it sounds fine for a while and then starts to degrade again. Any ideas how to resolve are appreciated.