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Bach 5GB (large shank) vs Bach 6½A (large shank)

The Bach 5GB (large shank) has a wider cup diameter, the Bach 5GB (large shank) 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 5GB (large shank)
    • Trombone
    Cup diameter25.50 mm / 1.0039 in
    Best suited for
    🎻Orchestral playing — large cup for full, dark tone
    📣High-volume projection — open throat for power
    vs
    Mouthpiece B
      Bach 6½A (large shank)
      • Trombone
      Cup diameter25.40 mm / 1.0000 in
      Best suited for
      🎻Orchestral playing — large cup for full, dark tone
      📣High-volume projection — open throat for power

      Cup Diameter

      The Bach 5GB (large shank) has a cup diameter of 25.50 mm / 1.0039 in compared to 25.40 mm / 1.0000 in on the Bach 6½A (large shank) — a difference of 0.10 mm / 0.0039 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 5GB (large shank) details Bach 6½A (large shank) details Bach 5GB (large shank) equivalents Bach 6½A (large shank) equivalents

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