Strange "beeping" when video paused

Hi

Using XBMCubunto on a zotac zbox hd-id41 (nvidia ion2 + dual core atom) I have issues with a strange beep/pulse sound whenever a video/audiois paused.

It is interesting to note that this beep does not happen if the audio/video is stopped

I'm currently running audio over HDMI

any ideas?

NOTE: i'm currently gathering debug log