Which has a bigger cup — Bach 12C or Bach 4C?

The Bach 4C has a cup diameter of 25.75 mm / 1.0138 in compared to 24.50 mm / 0.9646 in on the Bach 12C — a difference of 1.25 mm / 0.0492 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 12C and Bach 4C?

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

Bach 12C vs Bach 4C

Name: Bach 4C
Brand: Bach

The Bach 4C 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 12C

• Trombone

Throat diameter5.85 mm / 0.2303 in

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Bach 4C

• Trombone

Throat diameter5.85 mm / 0.2303 in

Best suited for

📣High-volume projection — open throat for power

Throat Diameter

Throat diameters are essentially identical at 5.85 mm / 0.2303 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.

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Bach 12C vs Bach 4C

Throat Diameter

Playing Characteristics

What Do These Model Names Mean?

What Changes If You Switch?

Which is better?

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Compare Bach 4C with others

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