TromboneChat

There is a high change that I have to double on marching tuba to help my former school. The event is in late October, and the school have only 1 tubist.

I have tried messing with tuba before (after horn and trumpet), but the result has not been good. The lower notes (from downward) spoke quite well, but the higher notes double buzzed to the point of unable to discern pitch. Yesterday, I tried using my bass mouthpiece (Yamaha 60BL to be specific) with a Yamaha BBb baby tuba (a YBB-105, probably). It fits, and the double buzz almost disappeared. The focusing was also better. I have not checked the intonation yet since I will not double on that particular tuba, and the tuba is beaten up and neglected to the point that the tuning slides cannot be moved.

Another thing that I am worrying is that when I return to my bass trombone, the focus of 2nd partial notes was all over the place, and it took me almost half an hour to get it back together again. The valve register was not affected, though.

Would a bass trombone mouthpiece fit large tuba shank? What is the problem I should expect to face using the setup? Is the concept of air of tuba different much from that of bass trombone? And what can I do to minimize the "confusion" of my embouchure?

A bass trombone mouthpiece won't fit in the large tuba shank as it's much bigger than the trombone shank. I haven't played too much tuba but what I've noticed is the air is mostly the same and it's a matter of having enough to fill the horn and using it to create a good sound. For the confusion of the embouchure, it should get easier the more you practice as you'll 'set' your tuba embouchure and differentiate it from your bass trombone one. But for a while there will be a bit of readjustment time until you get really comfortable with switching between the two. This can be mitigated by having a tuba mouthpiece that's similar to your bass mouthpiece, or as similar as possible. In the end, it's usually a matter of practice

I switch all the time takes lots of practice. I buzz the mps of each horn, easiest transition is between EEb tuba to bass tbn. I find a smaller rim tuba mps works good for me 32.6 mm. I play a Miraphone 191/1291. I play 113 de rim on bass Yama 611 and DG 6b

I played my first 47 performances of the Lion King (bass trb/tuba) on a top action Yamaha YBB-102 3-valve upright with a Bach 30CB contrabass trombone mouthpiece, and a King 7B Duo Gravis bass trombone.
The 30CB was especially helpful on the "come in cold" tuba/french horn duet in #2 "Mouse Music/Scar", which begins on an E in the staff, and ends with a slur from E up to middle C, and ends on a B below middle C.
The 30CB was a little loose in the tuba reciever, but "just fit". Since this was my debut on tuba, and my bass trombone mouthpiece was too loose in the tuba, the 30CB gave me a certain amount of security on the upper tuba parts. Not much unlike Kleinhammer using an Eb tuba mouthpiece for the heavy pedal work on bass trombone. As a matter of fact, the 30CB/Duo Gravis combination did work well on the "Stampede" pedal register parts.

Bill