Bach 17 vs Schilke 42
The Bach 17 has a wider cup diameter, the Schilke 42 has a larger throat opening.
Mouthpiece A
Bach 17
• Trombone
Cup diameter24.20 mm / 0.9528 in
Cup depthMedium
Rim width—
Throat diameter5.85 mm / 0.2303 in
Backbore—
Finish—
Material—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Schilke 42
• Trombone
Cup diameter23.22 mm / 0.9142 in
Cup depthMedium
Rim width—
Throat diameter5.95 mm / 0.2343 in
Backbore15/64 .2344"
Finish—
Material—
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Bach 17 has a cup diameter of 24.20 mm / 0.9528 in compared to 23.22 mm / 0.9142 in on the Schilke 42 — a difference of 0.98 mm / 0.0386 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Schilke 42 has a wider throat (5.95 mm / 0.2343 in vs 5.85 mm / 0.2303 in). A wider throat allows more air through, increasing volume and projection but reducing resistance.
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.