Bach 18 vs Yamaha BB-67B4
The Bach 18 has a wider cup diameter, the Bach 18 features a deeper cup, the Bach 18 has a larger throat opening.
The taper behind the throat leading to the shank. Affects projection and tone character.
Mouthpiece A
Bach 18
• Tuba
Backbore—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha BB-67B4
• Tuba
BackboreStandard
Best suited for
High-volume projection — open throat for power
Which is better?
Neither mouthpiece clearly dominates the other — the right choice depends on your embouchure, playing style, and the sound you're after. Try both if possible.