Schilke 58 vs Yamaha SL-53L
The Schilke 58 has a wider cup diameter, the Schilke 58 has a larger throat opening.
Cup Diameter
The Schilke 58 has a cup diameter of 27.68 mm / 1.0898 in compared to 25.91 mm / 1.0201 in on the Yamaha SL-53L — a difference of 1.77 mm / 0.0697 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 58 has a wider throat (7.54 mm / 0.2969 in vs 7.11 mm / 0.2799 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.