Bach 12C vs Schilke 51C4
The Schilke 51C4 has a wider cup diameter, the Schilke 51C4 has a larger throat opening.
The narrowest point at the bottom of the cup. Affects resistance, volume, and tone color.
Mouthpiece A
Bach 12C
• Trombone
Throat diameter5.85 mm / 0.2303 in
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Schilke 51C4
• Trombone
Throat diameter7.04 mm / 0.2772 in
Best suited for
High-volume projection — open throat for power
Throat Diameter
The Schilke 51C4 has a wider throat (7.04 mm / 0.2772 in vs 5.85 mm / 0.2303 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.