Which has a bigger cup — Bach 4 or Yamaha SL-48L?

The Bach 4 has a cup diameter of 26.00 mm / 1.0236 in compared to 25.25 mm / 0.9941 in on the Yamaha SL-48L — a difference of 0.75 mm / 0.0295 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 4 and Yamaha SL-48L?

Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.

Bach 4 vs Yamaha SL-48L

Name: Yamaha SL-48L
Brand: Yamaha

The Bach 4 has a wider cup diameter, the Yamaha SL-48L has a larger throat opening.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material

The taper behind the throat leading to the shank. Affects projection and tone character.

Mouthpiece A

Bach 4

• Trombone

Backbore—

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Yamaha SL-48L

• Trombone

BackboreSemi-narrow

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.