Firefox 4.0+ AND Chrome 13.0+ are supported.
However, Web Audio API doesn't seem enabled in Chrome 13 by default, just go to 'audio:flags', check "Web Audio", then click the "restart browser" button and it should work.
However, Web Audio API doesn't seem enabled in Chrome 13 by default, just go to 'audio:flags', check "Web Audio", then click the "restart browser" button and it should work.