my take is this. Go to a live acoustic jazz concert in a great sounding hall... and after an hour and 45 minutes you will be fatigued. If the emotional content, the degree of engagement in the music is high, then after a time (typically 1.5 hours or so) you will be fatigued.
In a stereo system, brightness, harshness, etc. can lead to fatigue. That is an entirely different thing. On the other end of the continuum, those who have systems that are "non-fatiguing" are systems that are not bright, not grainy sounding, etc. --- but if such systems are non-fatiguing even after 3-4 hours of dedicated listening... then the emotional content/degree of engagement in the music is minimal. That is, 1.5 hours of excellent music well recorded is fatiguing --- and 1.5 hours of grainy, harsh, bright music is also fatiguing. Bottom line... any session of dedicated listening is fatiguing after 1.5 hours or so... either for good reasons or bad (or a combo, in varying degrees, of both).
In a stereo system, brightness, harshness, etc. can lead to fatigue. That is an entirely different thing. On the other end of the continuum, those who have systems that are "non-fatiguing" are systems that are not bright, not grainy sounding, etc. --- but if such systems are non-fatiguing even after 3-4 hours of dedicated listening... then the emotional content/degree of engagement in the music is minimal. That is, 1.5 hours of excellent music well recorded is fatiguing --- and 1.5 hours of grainy, harsh, bright music is also fatiguing. Bottom line... any session of dedicated listening is fatiguing after 1.5 hours or so... either for good reasons or bad (or a combo, in varying degrees, of both).