Well, this is a shame.. Apparently the sample rate of the AudioContext (for some people 48 kHz) isn't definable (it should be 44.1 kHz here), which makes this a tough thing to fix. For me, it works in osx but not in windows 8 (bootcamp).
I found this: https://github.com/WebAudio/web-audio-api/issues/300
Apparently it's not implemented yet?
Uncaught NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer sample rate of 44100 does not match the context rate of 48000 Hz.
hpl.init_convolver main.js:464 hpl.init main.js:506 main.js:559 (anonymous function)