Which has a bigger cup — Bach 11C or Kelly 6-1/2AL-SS?

The Kelly 6-1/2AL-SS has a cup diameter of 25.15 mm compared to 24.70 mm on the Bach 11C — a difference of +0.45 mm. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 11C and Kelly 6-1/2AL-SS?

The Kelly 6-1/2AL-SS has a very deep cup while the Bach 11C has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.

Bach 11C vs Kelly 6-1/2AL-SS

The Kelly 6-1/2AL-SS has a wider cup diameter, the Kelly 6-1/2AL-SS features a deeper cup.

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

The width of the rim surface that contacts the lips. Wider rims improve endurance; narrower rims improve flexibility.

Mouthpiece A

Bach 11C

• Trombone

Rim width—

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Kelly 6-1/2AL-SS

• Trombone

General

Rim width—

Best suited for

🎻Orchestral playing — large cup for full, dark tone

📋Standard trombone / baritone

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 11C details Kelly 6-1/2AL-SS details Bach 11C equivalents Kelly 6-1/2AL-SS equivalents

Bach 11C vs Kelly 6-1/2AL-SS

Playing Characteristics

What Do These Model Names Mean?

What Changes If You Switch?

Which is better?

Compare Bach 11C with others

Compare Kelly 6-1/2AL-SS with others

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