[_spduchamp]

One of my favourite albums is Stuart Dempster's Underground Overlays From The Cistern Chapel.

A group of trombonists all playing in a giant underground water tank with incredibly long reverb.

https://youtube.com/watch?v=4tvMp4XDICU

[SoleilAbsolu]

That is awesome! Back in the '90s I participated in Tuba Christmas in NYC - I played sousaphone. The performance was on the Rockefeller Center ice rink, but the rehearsal was in the sub-sub basement parking garages of 30 Rock (I think).

Imagine hundreds of low brass players activating this enclosed volume of air - I've never experienced anything like it before or since!