def remove_offset(self):
"""
Convert the channel by removing the offset in the channel.
"""
newchannel = Channel()
newchannel.sampwidth = self.sampwidth
newchannel.framerate = self.framerate
a = AudioFrames( self.channel.get_frames(self.channel.get_nframes()), self.channel.get_sampwidth(), 1)
avg = a.avg()
newchannel.set_frames( a.bias( - avg ) )
self.channel = newchannel
