Listener fatigue: what does it really mean?

Distortion is the most likely suspect. High order distortion especially.

List of Possible Distortion Sources?

1. Comb filter effects

2. Tube microphonics

3. Cosmic microwave background radiation

4. Sunspot activity

5. Window vibration

6. Wall vibration

7. Floor vibration

8. Past Time coordinates embedded in recording

9. Directionality of wires, cables, fuses, etc.

10. Low pressure weather system

The Anstendig Institute has papers on this subject you might find helpful.

http://www.anstendig.org

check out the papers written under;

Vibrations: Natural and Mechanical

The body as a machine.

Our bodies are affected by the vibrational quality of our surroundings.

Hope this helps.

Agree with Csontos, it's the distortion. The problem is, even when you get rid of as much distortion as you can, there's still a great deal of distortion in the sound. We tend to assume that's what it's supposed to sound like, that any remaining distortion must be the fault of the recording. Pop Quiz: Where on Earth does all that remaining distortion come from?

"An ordinary man has no means of deliverance." - Old audiophile axiom

What does it really mean?

You're tired of listening to something to a point where you have to stop. To your boss, your wife, your kids, other audiophiles, and yes, even your audio system. I'm going to use a computer analogy. Sorry about that.

Hardware: I agree with many of the other comments here. Listening too loud, a piece of gear or a cable that's too harsh will kill you. Years ago I had a pair of Hales Design Group speakers. Good speakers but power hungry. I bought a Musical Fidelity amp without listening to it because I new it had the juice and the reviews were good, and I got a great deal. (BTW: good specs + good reviews + good deal - actually listening = stupid. learned my lesson) Within 2 minutes, I knew I was in trouble because the missus says: HMM, SOUNDS REALLY BRASSY. While it had the juice to drive the speakers, dynamics, and resolve - it was a brilliant Migraine Maker and it didn't last long. Even in the background I had to turn it off. And if you're wanting to turn off background music you're in deep sh*t.

Software: Some recordings are just harsh. I love the band Big Star and I downloaded a supposedly "Redbook quality digital file" from Rhino. Their recordings are edgy to begin with, but however Rhino encoded the digital files is just so shrill that I can't listen very long, even though I love the music. Also, the type of music you listen to can have an effect. I can handle about an hour of bebop. I love Scott Walker's experimental work, but I can only take one record at a time. Try listening to Gorecki Symphony 3 twice in a row at high volume without huddling up in a corner. Which brings me to...

User error: If you're actively listening to music, you don't leave YOU behind when you sit down in your fake Eames chair. YOU are the most important component in your system. Your mood, physical well-being, stress level, etc, all come along for the ride. If you have a great system without the hardware and software issues mentioned above, the music will transport you away from yourself, but you start there. And 90% of the time I get there. But sometimes I don't want to be hyper immersed. So I'll put on simpler music, or I walk away. Other times, and I'm embarrassed to admit this, I'm so transported that my monkey mind is shut down completely and I finally relax. Then fall asleep. But that is all me fatigue.

Here's a test. Drink a beer. Turn on your system. Drink another beer. Start listening. After a hour, are you bored, analyzing your set up? Drink another beer. Put on a favorite record. Still not happy? You probably have a hardware issue because your user issues should be greased.