Which has a bigger cup — Bach 12C or Kelly JAZZ-LS-SS?

The Kelly JAZZ-LS-SS has a cup diameter of 25.65 mm / 1.0098 in compared to 24.50 mm / 0.9646 in on the Bach 12C — a difference of 1.15 mm / 0.0453 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 12C and Kelly JAZZ-LS-SS?

The Kelly JAZZ-LS-SS has a — cup while the Bach 12C has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.

Bach 12C vs Kelly JAZZ-LS-SS

Name: Kelly JAZZ-LS-SS
Brand: Kelly

The Kelly JAZZ-LS-SS has a wider cup diameter, the Kelly JAZZ-LS-SS features a deeper cup.

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 12C

• Trombone

Backbore—

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Kelly JAZZ-LS-SS

• Trombone

Jazz

BackboreL

Best suited for

🎻Orchestral playing — large cup for full, dark tone

📋Jazz solo trombone

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 12C details Kelly JAZZ-LS-SS details Bach 12C equivalents Kelly JAZZ-LS-SS equivalents

Bach 12C vs Kelly JAZZ-LS-SS

Playing Characteristics

What Do These Model Names Mean?

What Changes If You Switch?

Which is better?

Compare Bach 12C with others

Compare Kelly JAZZ-LS-SS with others

Popular Trombone comparisons

Bach vs Kelly

Browse by specification