Bach 15 vs Schilke 38D
The Bach 15 has a wider cup diameter, the Bach 15 features a deeper cup.
Mouthpiece A
Bach 15
• Baritone / Euphonium
Cup diameter24.40 mm / 0.9606 in
Cup depthDeep
Rim width—
Throat diameter5.85 mm / 0.2303 in
Backbore—
Finish—
Material—
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
vs
Mouthpiece B
Schilke 38D
• Baritone / Euphonium
Cup diameter19.73 mm / 0.7768 in
Cup depthMedium
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
Cup Diameter
The Bach 15 has a cup diameter of 24.40 mm / 0.9606 in compared to 19.73 mm / 0.7768 in on the Schilke 38D — a difference of 4.67 mm / 0.1839 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 15 has a deep cup while the Schilke 38D 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.