Bach 18 vs Bruno Tilz 310-M 42
The Bruno Tilz 310-M 42 has a wider cup diameter, the Bach 18 has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 18
• Tuba
Cup diameter32.10 mm / 1.2638 in
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bruno Tilz 310-M 42
• Tuba
CatalogCup diameter33.00 mm / 1.2992 in
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Bruno Tilz 310-M 42 has a cup diameter of 33.00 mm / 1.2992 in compared to 32.10 mm / 1.2638 in on the Bach 18 — a difference of 0.90 mm / 0.0354 in. A wider cup generally produces a fuller, darker tone but requires more air support.
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.