As a native English speaker, I perfectly understand the meaning of “fatiguing.” I believe I conveyed that with my metaphor.
My question is in regard to its frequent use as in: “[fill in blank] was fatiguing” with no further explanation as to what aural characteristics contributed to this effect of fatigue.
I wasn’t asking for an explanation as to the general meaning of the word, rather, as to what is being conveyed in this specific usage.
Fatiguing is the feeling one gets. It can be caused by many different things, as I explained in the portion of
my earlier response that was added (the part after "Edited to add"), such as distortion (in the traditional sense of the word), irregularities in the frequency response, or something else that someone does not like about the sound after extended listening.
To directly address an earlier question of yours in your opening post:
How do I determine if any of my own gear is “fatiguing?”
It is fatiguing to you if you get the feeling of being fatigued after extended listening to it. If you don't get that feeling, then it is not fatiguing to you. It may, however, be fatiguing to someone else, as there may be some aspect of its sound that they don't like after extended listening.
"Fatiguing" is not an objective quality of the thing; it is a reaction to the thing.
What is fatiguing to one person may not be fatiguing to another. I will give an example. Some people love Klipsch speakers, regarding them as the pinnacle of perfection, and others hate them. They tend to be a very polarizing brand. Rather than get mired in the fact that different models have different characteristics, I will discuss only the quintessential Klipsch speaker, the Klipschorn, to illustrate my point.
With speakers, the first little movement of a cone (or dome or ribbon or whatever) is typically very easy to do, with little physical resistance to that movement. But as one gets nearer the limits of the excursion of the driver, the physical resistance is greater. You can test this for yourself by gently pushing on a woofer cone, when you are not playing music. The first tiny movement requires very little force, but when you push the cone further, getting near the limits of how far it can safely move, it requires more force to move it than it did for the first tiny movement. This has an effect on the sound, as it also means that when one is trying to push the cone electrically (as when music is played through it), the greater physical resistance to the movement of the cone near its limits will cause it to compress the dynamic range of the music, because the cone is not moving as far for the music at that point as it was for the initial movement of the speaker. This effect can be minimized by not ever playing music that pushes the speaker near its limits, with the less hard one pushes the driver, the less of an issue this is.
This relates to a virtue of the Klipschorn, because it is capable of playing much louder in an ordinary room than one would normally play music (if one keeps the volume at sane levels that are not doing permanent damage to one's hearing). This same virtue can be had with any speaker designed to fill a large auditorium with sound, but used in an ordinary sized living room; another such speaker that people have loved is the Altec A7 "Voice of the Theatre," but I will continue just with the discussion focused on the Klipschorn to keep us from getting sidetracked by irrelevant aspects of the different possible options. What matters for this discussion is the fact that the Klipschorn has a high sensitivity combined with a reasonable power handling ability that enables it to play extremely loud in an ordinary living room. As such, as long as one listens at sane levels, one never pushes the speaker hard, and so one does not have much dynamic compression when using this speaker in an ordinary living room. This is why some describe it as having "effortless dynamics," as the dynamic range is largely preserved with this speaker.
Most speakers that people listen to in their homes do not have the ability to play as extremely loud as the Klipschorn, and so most speakers will exhibit more dynamic compression with music than the Klipschorns, because most speakers will be driven nearer their limits (since they are more limited in their maximum volume). And the louder one plays the music, the more one will experience this compression of the dynamic range, as one is getting closer to the limits of the speaker. So this will tend to be more important to people who listen to music at high levels, though exactly how loud this will be noticeable depends on the specific speakers we are comparing, along with the acoustics of the room in which they are placed, etc.
Some people highly value this aspect of the sound, and so some people love Klipschorns.
However, there are other characteristics of Klipschorns that are not so desirable (at least, not desirable if one wants the speaker to accurately reproduce what is sent to it). I will just mention one characteristic and not concern myself with other characteristics that may also be a factor in such judgements. If one looks at the measurements here:
Sidebar 3: Measurements Because of the Klipschorn AK6's bulk—each weighs 220 lb—I drove my test gear the 177 miles to Art's place and measured the speaker sitting on a furniture dolly in his driveway. I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Klipschorn's...
www.stereophile.com
One can see that the frequency response is a mess. Especially given the fact that those are (were in 2019)
$15,000 per pair speakers, that is a horribly bad frequency response. But it is bad for a speaker at a much lower price; it is easy to get a better, flatter frequency response with speakers under $1k. So, some people are going to hate the Klipschorn because of its extremely poor frequency response.
How one feels about them is going to depend greatly on what characteristics of the sound matter to the listener, as the Klipschorn objectively has qualities that make it higher fidelity than most speakers, and also lower fidelity than many speakers with pretentious to being high fidelity speakers.
("Fidelity" means faithfulness, as many audiophiles forget; to be "high fidelity" means that the thing reproduces the input to a high degree without adding or subtracting from the original signal. So there are objective qualities about what it is to be "high fidelity," though whether someone likes the equipment to be more faithful to the original signal or not is a matter of subjective preference.)
So, are Klipschorns good speakers? Well, from the standpoint of dynamic compression, they are great, but from the standpoint of the frequency response, they suck. So, some people love them, and some people hate them.
(I, on the other hand, appreciate what is good about them, but don't like what is bad about them. So I neither love nor hate them.)