Bach 6½AL (large shank) vs Schilke 51C4
The Schilke 51C4 has a wider cup diameter, the Bach 6½AL (large shank) features a deeper cup, the Schilke 51C4 has a larger throat opening.
The taper behind the throat leading to the shank. Affects projection and tone character.
Mouthpiece A
Bach 6½AL (large shank)
• Trombone
Backbore—
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
vs
Mouthpiece B
Schilke 51C4
• Trombone
BackboreJ .277"
Best suited for
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.