Yeah I was a tubist. Timpanis were arms length away, I have to assume that the effect is only for French Horn players…that tiny mouthpiece and the continuous tapering and the intense flare at the end…it’s also aimed a funny direction compared to the other brass instruments (a little to the side rather than up or straight ahead).

In a semi-confined space too - eg an orchestra pit at the opera... Musician wins landmark ruling over ruined hearing (2018) https://www.bbc.co.uk/news/entertainment-arts-43571144

Eargasm...

To expand a bit on that: it's a brand of musicians earplugs.