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Bach 18 vs Bob Reeves 4G/JF

The Bob Reeves 4G/JF has a wider cup diameter, the Bob Reeves 4G/JF features a deeper cup.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material
Mouthpiece A
    Bach 18
    • Trombone
    Cup diameter24.20 mm
    Cup depthMedium
    Rim width—
    Throat diameter5.85 mm
    Backbore—
    Finish—
    Material—
    Best suited for
    📣High-volume projection — open throat for power
    vs
    Mouthpiece B
      Bob Reeves 4G/JF
      • Trombone
      Cup diameter26.00 mm
      Cup depthDeep
      Rim width—
      Throat diameter—
      Backbore—
      Finish—
      Material—
      Best suited for
      🎻Orchestral playing — large cup for full, dark tone

      Cup Diameter

      The Bob Reeves 4G/JF has a cup diameter of 26.00 mm compared to 24.20 mm on the Bach 18 — a difference of +1.80 mm. A wider cup generally produces a fuller, darker tone but requires more air support.

      Cup Depth

      The Bob Reeves 4G/JF has a deep cup while the Bach 18 has a medium 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 18 details Bob Reeves 4G/JF details Bach 18 equivalents Bob Reeves 4G/JF equivalents

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