Kelly 6-1/2AL-SS vs Schilke 45B

The Kelly 6-1/2AL-SS has a wider cup diameter, the Kelly 6-1/2AL-SS features a deeper cup.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material
Mouthpiece A
    Kelly 6-1/2AL-SS
    • Trombone
    General
    Cup diameter25.15 mm
    Cup depthVery deep
    Rim width
    Throat diameter
    BackboreM
    Finish
    Material316 Surgical Stainless Steel
    Best suited for
    🎻Orchestral playing — large cup for full, dark tone
    📋Standard trombone / baritone
    vs
    Mouthpiece B
      Schilke 45B
      • Trombone
      Cup diameter24.30 mm
      Cup depthMedium
      Rim width
      Throat diameter5.95 mm
      Backbore15/64 .2344"
      Finish
      Material
      Best suited for
      📣High-volume projection — open throat for power

      Cup Diameter

      The Kelly 6-1/2AL-SS has a cup diameter of 25.15 mm compared to 24.30 mm on the Schilke 45B — a difference of +0.85 mm. A wider cup generally produces a fuller, darker tone but requires more air support.

      Cup Depth

      The Kelly 6-1/2AL-SS has a very deep cup while the Schilke 45B has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.

      Material

      The Kelly 6-1/2AL-SS is described as 316 Surgical Stainless Steel, and the Schilke 45B as unspecified. Material affects mass, warmth, and how quickly the piece responds.

      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 6-1/2AL-SS details Schilke 45B details Kelly 6-1/2AL-SS equivalents Schilke 45B equivalents