how do you avoid listener fatigue

Here are some infos I've found that may help: Distortion

Clipping is the most commonly heard kind of distortion (clipping distortion) and is very objectionable on voice and other monotonic (one tone or sound at a time) sounds. A similar amount of clipping distortion applied to some kinds of music is not quite as audible but is still a problem. Even amounts that are not explicitly noticeable to a given listener will still lead to greater listener fatigue. They may not know why they don't want to listen any more but it happens nevertheless.

Individuals vary in their ability to hear distortion (or at least to identify what they're hearing). I'm often surprised when others claim not to be able to hear the problem that I'm finding so objectionable I need to turn the radio off! http://www.prometheusradio.org/audio_processing_and_compressors

FM Station – Smooth Listening (Favorite FM ) This is the newest preset for long time listening. The high frequency part is compressed more deeply according to the FM Pre-emphasis characteristics. http://homepage2.nifty.com/toshi-software/help/fabulousmp3/help_e/preset.html