What is the implication of changing audio to Mafw (apart from enabling volume control when screen locked)?

I find the N900 audio frustratingly obtuse at times, although it appears to be very powerful on paper. High-bitrate FLACs sound 'off' although they play, there appears to be distortion in Media Player audio at times, and there's occasional channel-swapping (once again in Media Player) for what appears to be no good reason - which also affects QSpot.