The feature was first spotted in a Chromium and Canary build, the Animated Audio indicator in each tab is expected to have a throbber animation that will cycle over numerous frames on a bitmap. However there are currently only 6 frames that are good enough for testing.
According to the reports, the indicator will be placed over the 'favicon' and will be animated so it will be easy to spot it. The look and functionality of the feature may be expanded as it is not available in the Chrome Dev channel yet. This also means there is no guarantee it will actually make it to the browser. The Audio Indicator feature is now available for Flash sites and support for plugins is also being developed.
This new Animated Audio feature will help identify tabs that play irritating loud sounds. It will be particularly helpful to users who like to open multiple tabs at once. Google says that this tweak will help in differentiating and discarding tabs whose memory runs out. The Audio animation will help you keep track of active tabs when you have numerous tabs open simultaneously in your browser window.
Source: The Next Web