Also about two weeks ago, we had a "home concert" in our formal living/dining as a function of our church, inviting a professional soprano soloist and pianist, and over 50 people as the audience. During a rehearsal session, out of curiosity I measured the SPL of live performance at 8'-10' away from the artists. The peak SPL at the fortissimo attacks of the piano readily went up to 105dB. But as you can imagine, the performance never sounded "too loud." We own a decent Yamaha grand piano, but it is by no means the "concert" size -- it is just a home-size grand. I think a full-concert grand piano is readily capable of 108dB peak SPL or so, when measured that close.
Of course, there is a HUGE difference in perceived loudness between those "noise sources" that produce high steady-state SPL, and the live acoustic music with much lower average SPL and occasional high peaks.
When I seriously listen to music or watch movies, the peak SPL at listening position will easily go up to 105dB or so. chess, I guess you have been too civilized and conservative when it comes to the sound level.
