Which has a bigger cup — Bach 3D or Bach 7D?

The Bach 3D has a cup diameter of 16.30 mm / 0.6417 in compared to 16.20 mm / 0.6378 in on the Bach 7D — a difference of 0.10 mm / 0.0039 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 3D and Bach 7D?

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

Bach 3D vs Bach 7D

Name: Bach 7D
Brand: Bach

The Bach 3D has a wider cup diameter.

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 3D

• Cornet

Backbore—

Mouthpiece B

Bach 7D

• Cornet

Backbore—

Best suited for

🎺Lead / commercial — shallow cup for brightness and range

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.