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Bach 12C vs Bach 7C

The Bach 7C has a wider cup diameter.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
    Bach 12C
    • Trombone
    Cup diameter24.50 mm / 0.9646 in
    Best suited for
    📣High-volume projection — open throat for power
    vs
    Mouthpiece B
      Bach 7C
      • Trombone
      Cup diameter24.75 mm / 0.9744 in
      Best suited for
      📣High-volume projection — open throat for power

      Cup Diameter

      The Bach 7C has a cup diameter of 24.75 mm / 0.9744 in compared to 24.50 mm / 0.9646 in on the Bach 12C — a difference of 0.25 mm / 0.0098 in. A wider cup generally produces a fuller, darker tone but requires more air support.

      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 Bach 7C details Bach 12C equivalents Bach 7C equivalents

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