Yamaha BB-65 vs Yamaha BB-66D4
The Yamaha BB-66D4 has a wider cup diameter, the Yamaha BB-66D4 features a deeper cup, the Yamaha BB-66D4 has a larger throat opening.
The taper behind the throat leading to the shank. Affects projection and tone character.
Mouthpiece A
Yamaha BB-65
• Tuba
BackboreSemi-wide
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha BB-66D4
• Tuba
BackboreSemi-wide
Best suited for
Orchestral playing — large cup for full, dark tone
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.