Which has a bigger cup — Bach 8½A or Kelly 5C?

The Kelly 5C has a cup diameter of 16.76 mm / 0.6598 in compared to 16.10 mm / 0.6339 in on the Bach 8½A — a difference of 0.66 mm / 0.0260 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 5C?

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

Bach 8½A vs Kelly 5C

Name: Kelly 5C
Brand: Kelly

The Kelly 5C has a wider cup diameter, the Kelly 5C has a larger throat opening.

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

Base metal or construction (e.g. brass, stainless steel, plastic). Influences weight, response, and tone color.

Mouthpiece A

Bach 8½A

• Cornet

Material—

Mouthpiece B

Kelly 5C

• Cornet

General

MaterialLexan polycarbonate

Best suited for

📣High-volume projection — open throat for power

📋Mid-range all-purpose

Material

The Bach 8½A is described as unspecified, and the Kelly 5C as Lexan polycarbonate. Material affects mass, warmth, and how quickly the piece responds.

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.

Open in interactive tool + Add third mouthpiece Bach 8½A details Kelly 5C details Bach 8½A equivalents Kelly 5C equivalents

Bach 8½A vs Kelly 5C

Material

Playing Characteristics

What Do These Model Names Mean?

What Changes If You Switch?

Which is better?

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