Archived:Background noise while streaming zero-filled buffers (Known Issue)
In some S60 2nd and 3rd Edition devices the level of background noise may be disturbing when using an audio output stream to play back silence; that is, when the stream is fed with zero-filled buffers.
Applications should not implement a 'mute' functionality by streaming zero-filled buffers. Instead, the output stream should either be stopped or its volume level should be set to 0.
Note that adjusting the volume is a significantly faster operation than stopping/restarting the stream.