HTML5 / JS Audio: Real-time audio mixing possible?

Question

Does someone have an overview of the browser audio APIs situation today (Oct 2012)?

Is it possible today to create synchronized realtime mixing of several (2 to 6) MP3 audio files?

If not, are there any work going on (alpha, beta) that will make this possible?

Answer 1

Here is a great overview of the Web Audio API, which allows sound mixing. However the support chart does not look very good.