Which has a bigger cup — Bach 8½A or Kelly 3C?

The Kelly 3C has a cup diameter of 17.02 mm / 0.6701 in compared to 16.10 mm / 0.6339 in on the Bach 8½A — a difference of 0.92 mm / 0.0362 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 8½A and Kelly 3C?

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

Bach 8½A vs Kelly 3C

Name: Kelly 3C
Brand: Kelly

The Kelly 3C has a wider cup diameter, the Kelly 3C has a larger throat opening.

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

Surface plating or treatment (e.g. silver plate, gold trim). Affects feel, durability, and appearance.

Mouthpiece A

Bach 8½A

• Cornet

Finish—

Mouthpiece B

Kelly 3C

• Cornet

General

Finish—

Best suited for

🎻Orchestral playing — large cup for full, dark tone

📣High-volume projection — open throat for power

📋All-purpose mid-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.