Which has a bigger cup — Bach 8¾ or Bach 9A?

The Bach 8¾ has a cup diameter of 16.10 mm / 0.6339 in compared to 16.05 mm / 0.6319 in on the Bach 9A — a difference of 0.05 mm / 0.0020 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 8¾ and Bach 9A?

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

Bach 8¾ vs Bach 9A

Name: Bach 9A
Brand: Bach

The Bach 8¾ has a wider cup diameter.

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

The narrowest point at the bottom of the cup. Affects resistance, volume, and tone color.

Mouthpiece A

Bach 8¾

• Cornet

Throat diameter3.66 mm / 0.1441 in

Mouthpiece B

Bach 9A

• Cornet

Throat diameter3.66 mm / 0.1441 in

Throat Diameter

Throat diameters are essentially identical at 3.66 mm / 0.1441 in, so resistance feel will be comparable.

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.