This is true, but that is not to say solutions are not on their way. From this script that was submitted yesterday (https://gist.github.com/9c4955e5a3662e4cd5e1):

https://wiki.mozilla.org/Audio_Data_API

http://chromium.googlecode.com/svn/trunk/samples/audio/speci...

Real-time audiosynthesis is coming, but it will take a while to reach the level that Flash currently offers.

Audio is always a tricky topic because things like timing are so much more sensitive then the standard render-centric run loop. Audio control tends to fall outside the event based models that work so well for GUIs.

Though it comes at the expense of CPU usage, running a GUI on a strictly-timed frame-synced loop makes interaction much, much smoother.

Soundmanager 2.0: http://www.schillmania.com/projects/soundmanager2/

A much too long article which basically says two things: HTML5 audio doesn't allow raw access to the audio data (which could be used for sample generation, making a spectrum analyzer, etc.), and doesn't have the fine control over timing that a game developer might hope for.

I said it shorter in tweets (@cromwellian), but the Microsoft IE9 guy didn't get it, hence the rant. It turns out, many people do not understand the timing issues as you might think. The Microsoft guy seems to think you can string together serial audio using Javascript's setInterval() despite non-determinism sources from Garbage Collection, browser style recalculation/layout, and other event-loop events interfering.