fixed voice chat on mac (and generally all systems)

Ignore-this: cc3997c840616347b6c33033fc7a14c7

Fixed audio recording on mac. Mac sent fewer got_sound events and because I had a
bug in the algorithm the sound was poor. This didn't show up on windows or linux.

darcs-hash:20141109034816-c21fe-b87233ffe829919c434fdcb83629839ec6d8d015