I still have some problem with you insistance with >120 db output levels though .. Often you even speak of mortar shots! .. It is not safe to listen at these levels even if one system's is capable of such ...
The human ear has a range of different SPLs vs. frequency as pain threshold. We can tolerate a lot at 10Hz, ear-wise, whereas at 3KHz, we are prone to cringing. For some folks, fingernails dragged across a blackboard... you get the point.
Constant noise levels are fatiguing. Anything constant, whether loud or not so loud, can be unpleasant.
Let's consider music. The more dynamic it is, the better we tolerate brief transient periods of much greater loudness. Percussive music can enjoy a large dynamic aperture, as music goes, so often we tolerate some rather loud sounds because our ears are average-weighted--meaning that we don't perceive brief sounds as strongly as sustained sounds.
Music with deep, intense bass levels is another situation where more loudness is often tolerated. If the bulk of the energy is away from the ear's sensitive range in the upper midrange, people will tolerate more SPLs, until the point of bodily discomfort. A screaming lead guitar in a dense mix will be less tolerable than a heavy bass riff with little else filling up the 'white space' around it. This is the situation where levels above 120dB can still be enjoyable.
Another situation is reality hi-fi: event recordings, such as fireworks, a battlefield, a shuttle launch, etc. Here, SPLs can easily surpass 120dB on a regular basis. Yet we tolerate it, because we want to see the rare event. The noise is still part of the experience.
Part of realistic reproduction of sound is encompassing the upper range of SPLs without effort. Because even 1% distortion can change the sound of an explosion. Minor thermal compression, even minor clipping will change the impact of an explosion. Ever notice how a .38 S&W snubnose seems to crack your head open with it's ear-splitting report when fired? Most of the time when we hear a recording of a gunshot, the top 60 decibels are missing. It's obviously fake. But when you go to Broadway to see Miss Saigon and in the final act when Kim shoots herself, the report is startlingly loud in a theater, because it's a real gunshot, not one that was recorded, compressed and played through a sound system whose designers did not anticipate the need to repro a gunshot. A lot of movie audio seems to be designed to insulate us from the harsh reality of the real life scene, or maybe it's to accomodate the lower 99% of home theater systems and TV sets' audio capabilities.
Aside from the proper reproduction of any sound that doesn't kill you, the advent of modern music, like Reggae, Urban, Rock, Disco, Funk, etc., with the types of instruments that sound 'believable' at high levels of loudness, if one is diggin' the beat, body chemistry undergoes a change which results in increased endorphines and a euphoric state which not only increases the tolerance of loudness, but also increases the DESIRE for increased loudness.
For me, on a personal note, I find certain pop music from Japan and Korea to be stimulating, and the desire to turn it way up, very strong. This has also happened with some American music over the years. Dick Dale and the Deltones, later followed by Three Dog Night, Tommy James (when he moved to psychodelic rock), The Doors, Creedance Clearwater Revival, Bob Marley and others, have produced music that sounds better as it gets louder.
Then, there is a whole 'nother aspect.. I call it "Tactile Experience". It doesn't start to play a role until you get well over 120dB. In fact, it is best experienced over 140dB, because that's where you start to get the gut moving. The air turns to a solid mass around you. Your breathing is now controlled by the beat of the music. Air friction is rapidly warming the air in the room. You start to sweat in seconds. A sense of borderline out of control panic sets in. Your pulse quickens, but you can't feel it because of the pulse of the music. You're experiencing an adreneline rush. At this point, your ears feel like someone is running a pipe cleaner through your eardrums, but you don't care, because pain is pleasure is ecstacy because you're diggin' the beat. You can't perceive the melody much anymore, but you make an interesting mental note that the pitch of the music decreases when you plug your ears with your fingers, and goes up again about a semitone when you unplug your ears. Then you raise the volume another 8 dB or so for the orgasmic climax, as the room around you starts to self destruct and objects start falling from the ceiling. Glass is breaking, but everything seems to happen in slow motion and you can't hear anything but the music, so it is not real, so your brain says. You roll back the volume before blood shoots out of your ears, and a moment later the song ends. Your legs and arms have become jelly. You feel totally exhausted. But you feel SATIATED.
Great hi-fi is better than sex. It is the only orgasm that you can extend into minutes, or, longer. For music to be a whole body experience, it must shake the body, violently, existentially telling the body who's boss--who's in control.
This.. is why you need SPL in excess of 120dB sometimes.