Bach 18 vs Schilke 67
The Schilke 67 has a wider cup diameter, the Bach 18 has a larger throat opening.
Mouthpiece A
Bach 18
• Tuba
Cup diameter32.10 mm / 1.2638 in
Cup depthMedium
Rim width—
Throat diameter9.00 mm / 0.3543 in
Backbore—
Finish—
Material—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Schilke 67
• Tuba
Cup diameter32.41 mm / 1.2760 in
Cup depthMedium
Rim width—
Throat diameter8.33 mm / 0.3280 in
Backbore21/64.3281"
Finish—
Material—
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Schilke 67 has a cup diameter of 32.41 mm / 1.2760 in compared to 32.10 mm / 1.2638 in on the Bach 18 — a difference of 0.31 mm / 0.0122 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Bach 18 has a wider throat (9.00 mm / 0.3543 in vs 8.33 mm / 0.3280 in). A wider throat allows more air through, increasing volume and projection but reducing resistance.
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.