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Bach 12C vs Bach 30CB

The Bach 30CB has a wider cup diameter, the Bach 30CB features a deeper cup.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material
Mouthpiece A
    Bach 12C
    • Trombone
    Cup diameter24.50 mm / 0.9646 in
    Cup depthShallow
    Rim width—
    Throat diameter5.85 mm / 0.2303 in
    Backbore—
    Finish—
    Material—
    Best suited for
    📣High-volume projection — open throat for power
    vs
    Mouthpiece B
      Bach 30CB
      • Trombone
      Cup diameter30.00 mm / 1.1811 in
      Cup depthVery deep
      Rim width—
      Throat diameter—
      Backbore—
      Finish—
      Material—
      Best suited for
      🎻Orchestral playing — large cup for full, dark tone

      Cup Diameter

      The Bach 30CB has a cup diameter of 30.00 mm / 1.1811 in compared to 24.50 mm / 0.9646 in on the Bach 12C — a difference of 5.50 mm / 0.2165 in. A wider cup generally produces a fuller, darker tone but requires more air support.

      Cup Depth

      The Bach 30CB has a very deep 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.

      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 30CB details Bach 12C equivalents Bach 30CB equivalents

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