Hi guys,
Just to let you know, I've suddenly started having the same problem!
I'm using a macbook btw.
I hear phrases relating to current news articles, so I believe I may be receiving audio from a news channel. The audio never lasts long enough for me to record it or anything. It as happened a few times today but only for about 5 seconds each time.
I don't have any external speakers connected.
I'm connected to the internet via a passworded wifi. I've only really noticed the sound when I have safari open, but it's not coming from any of the web pages I am on. I have managed to close all the tabs etc of safari and the audio will continue but the bursts are short.
I have run a virus scan with iAntiVirus and nothing has come up. I have deleted my cache and cookies, but the sound is still ocuring.
Any ideas? It's a little worrying. No I'm not crazy!!