Bach 12C vs Bach 15E
The Bach 12C has a wider cup diameter.
How deep the cup is, from shallow (brighter, easier high register) to deep (darker, fuller sound).
Mouthpiece A
Bach 12C
• Trombone
Cup depthShallow
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 15E
• Trombone
Cup depthShallow
Best suited for
High-volume projection — open throat for power
Cup Depth
Both mouthpieces share a shallow cup depth, so the sound character from depth alone will be very similar.
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.