Of course, this was ridiculous, and we were actually trying to see if we could get the music director to tell us that we were playing too loud. He never did. (This was a reading rehearsal.) He tended to listen to a lot of recordings with headphones, and - as we all know - many orchestral recordings are mixed to sound over the top.
(One of the first digitally recorded classical albums (ever) was of the Atlanta Symphony playing this piece - and Firebird on the flip side - back many decades ago, and - since there were no digital media - it was released on an LP, but this passage sounded basically like this on that LP and I had sent the modern day YouTube link to my bass trombone colleague here before this rehearsal... We had chuckled about it and it prompted what you hear.)
27,000 YouTube views is quite revealing as to what tuba players are really into - as far as music is concerned, yes?
That said, IF a C tuba, THEN a 16-1/2 inch bell handmade 186...
I bought this thing out of curiosity. This was the same day it arrived in the box with no packing materials. The bottom bow had a football shaped flat dent in the bottom that was about 7 inches long and perhaps 3 inches wide. There were cobwebs in the bell, the linkage and rotors clanked like crazy, and the cork plate bumpers were way out of regulation.
It arrived just before I had to leave for this rehearsal, and I tossed it in the car - having done nothing to anything, so you're hearing the sonority enhanced by the cobwebs and the column of air sped up
(I went ahead and used this thing on the concert, also without having done anything to it.)

