SecretNoisyWebPages

I'm using either Opera, Firefox or Safari (at school) to surf the web. After some time online, I usually have 5-15 open tabs on my browser. at this time, a seriously annoying problem often occures:

One of the web-pages seems to be playing sound - But I have no idea which one!

Usually, when this happens, I begin obsessively going through all the open tabs and search for the page that is most likely making the noise (myspace pages, wierd full-screen flash sites, etc).

This is clearly the case of user frustration. I have a few tabs open, and let's say I want to make the noise stop asap, I now have to close each noise candidate - but in many cases I find out that I had closed the wrong page, or worse, I get 2 pages playing some music at the same time.

This brings several questions to mind:

• Can (and should?) my browser indicate that a tab-page is causing soundplay?
• Can I have a mute button on my browser (I would certainly like one)
• Do people that create noisy web pages never use a tabbed-browser to surf to their own pages?
  

One last note on the subject is that Opera's (genious) Undo feature allows me to do trial and error on closing tabs to find out just the right one. If I accidently choose the wrong tab to close and still head sound playing, I Ctrl+Z it back and try the next one.