Bach 18 vs Schilke 45
The Schilke 45 has a wider cup diameter, the Schilke 45 has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 18
• Trombone
Cup diameter24.20 mm / 0.9528 in
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Schilke 45
• Trombone
Cup diameter24.38 mm / 0.9598 in
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Schilke 45 has a cup diameter of 24.38 mm / 0.9598 in compared to 24.20 mm / 0.9528 in on the Bach 18 — a difference of 0.18 mm / 0.0071 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.