Schilke 40 vs Schilke 43A
The Schilke 43A has a wider cup diameter.
Mouthpiece A
Schilke 40
• Trombone
Cup diameter22.53 mm / 0.8870 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
vs
Mouthpiece B
Schilke 43A
• Trombone
Cup diameter23.57 mm / 0.9280 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 Schilke 43A has a cup diameter of 23.57 mm / 0.9280 in compared to 22.53 mm / 0.8870 in on the Schilke 40 — a difference of 1.04 mm / 0.0409 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
Throat diameters are essentially identical at 5.95 mm / 0.2343 in, so resistance feel will be comparable.
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.