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Hi

I've been pondering ... I once saw a Yamaha 822F with a 15" bell ... from what I gathered, someone had put a 15" bell from a Besson horn on the Yamaha. Would that be possible?

It sounded perfect for what I'm looking for - I currently have a Yamaha 822F but I far prefer the sound of my old Yamaha YBB621 - but wanted a easier blowing high register for solo stuff. I love helicons and that agressive sound, rather than than the round "tuba-y" sound.

Any thoughts?

Thanks!

I might be wrong, but I think the 822 F and 321 Eb are the same size at the bottom of the bell, so that might be an option for a bell source. I might be interested in your 822 bell if you decide you don't want it...

-T. J.

I've said it in private, but I don't 'really' know...

That bell change has got to mess with the tuning, surely....

As long as they are the same height, it should be very close, as long as the only difference is the bell flair

Bell diameter plays a part in the effective acoustic length of brass instruments (and thus tuning). Google "end effect". Quoting myself from an old thread:

Don't forget the "end effect" of the bell: effective tube length = actual tube length + (0.6 * bell diameter) The working length of the tuba actually extends past the end of the bell, and bell diameter makes a difference.

UncleBeer wrote:Bell diameter plays a part in the effective acoustic length of brass instruments (and thus tuning). Google "end effect". Quoting myself from an old thread:

Don't forget the "end effect" of the bell: effective tube length = actual tube length + (0.6 * bell diameter) The working length of the tuba actually extends past the end of the bell, and bell diameter makes a difference.

What would the formula for this look like? It would be very useful when "prototyping" tubas...

I didn't know that, learn something new every day

roweenie wrote: What would the formula for this look like? It would be very useful when "prototyping" tubas...

If a bell had a diameter of (say...) 50cm, you'd multiply that figure by 0.6 to find the end effect. A bell of that diameter adds 30cm to the effective length of the tuba.

So, does that mean the length of a CC tuba (192", 12"×16') with a 19" bell, actually really needs to be @ 181" (192-[19×.6])?

Just trying to understand the effect in relation to intonation.....

Yep, you've got it. BUT...there are other factors at play when determining instrument length like volume. A 'fatter' instrument doesn't have to be as long. That's why euphs are shorter than trombones, even though they're in the same key.