Kelly 5G vs Marcinkiewicz 8H-S

The Marcinkiewicz 8H-S has a wider cup diameter, the Kelly 5G 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
    Kelly 5G
    • Trombone
    Orchestral
    Cup diameter25.40 mm / 1.0000 in
    Best suited for
    🎻Orchestral playing — large cup for full, dark tone
    📋Symphonic trombone
    vs
    Mouthpiece B
      Marcinkiewicz 8H-S
      • Trombone
      Cup diameter26.06 mm / 1.0260 in
      Best suited for
      📣High-volume projection — open throat for power

      Cup Diameter

      The Marcinkiewicz 8H-S has a cup diameter of 26.06 mm / 1.0260 in compared to 25.40 mm / 1.0000 in on the Kelly 5G — a difference of 0.66 mm / 0.0260 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 Kelly 5G details Marcinkiewicz 8H-S details Kelly 5G equivalents Marcinkiewicz 8H-S equivalents