Where does fatique come from?

fatigue, in the neurological sense occurs after one reaches the adaptation level--sorry, you may need to go to the psychology books.

essentially, the rate of firing of neurons decreases to the extent that one's ability to differentiate is severely undermined.

using theaforementioned concept, a consistent and significant sonic signature of any nature, can induce "fatigue", after a period of time, which is listener dependent.

fatigue can occur, as has been suggested when one attempts to focus, i.e., listen critically and analyze, for some period of time.

could the word "fatigue", in the context of this thread, connote displeasure with the sound of a stereo system, rather than enervation ?

if so, any serious imbalance in frequency response can be annoying, even for a short time, without producing neurological fatigue, or a sense of physiologoical fatigue.

listening to music can be relaxing if one listens for pleasure rather than to assess the sound quality of a recording or stereo system.

perhaps superficial listening is a way of avoiding fatigue. if your nerves aren't firing to much to begin with, you won't have to be concerned with a slow down.