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Bach 12E vs Bach 9

The Bach 9 has a wider cup diameter, the Bach 9 features a deeper cup.

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 12E
    • Trombone
    Cup diameter24.50 mm / 0.9646 in
    Best suited for
    📣High-volume projection — open throat for power
    vs
    Mouthpiece B
      Bach 9
      • Trombone
      Cup diameter24.72 mm / 0.9732 in
      Best suited for
      🎻Orchestral playing — large cup for full, dark tone
      📣High-volume projection — open throat for power

      Cup Diameter

      The Bach 9 has a cup diameter of 24.72 mm / 0.9732 in compared to 24.50 mm / 0.9646 in on the Bach 12E — a difference of 0.22 mm / 0.0087 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 12E details Bach 9 details Bach 12E equivalents Bach 9 equivalents

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