I have a similar problem to the one described here http://www.bleepingcomputer.com/forums/t/252529/bubble-popping-noise/
This is on my work computer, so I don't have the speakers hooked up all the time, however I need sounds for one thing or another, this last time I was constantly bombarded with a series of, what sounds to me, like poping bubbles.
It plays at irregular intervals, sometime in quick succession and sometimes going a minute or more between repetitions. It is none of the sounds referenced in the linked thread, this one is much longer.
I've gone into the Sounds and Audio Device menu of the control panel and set the sound scheme to None.
My desktop wall paper is 'none' with a black background.
I have seen no action/reaction pattern to this sound.
It is very annoying.
Muting the volume at the system tray give me silence.
The last time I used the speakers was over a month ago and this problem was not happening.
And finally, I don't know if this has anything to do with anything, but in the last 4-6 weeks, whenever I unlock my station 2 'Programs' windows span for no known reason. I mention this because it started because between the time the sounds was behaving and now.