Yamaha SL-48S-GP vs Yamaha SL-YEO-S
The Yamaha SL-YEO-S has a wider cup diameter, the Yamaha SL-YEO-S features a deeper cup, the Yamaha SL-YEO-S has a larger throat opening.
Cup Diameter
The Yamaha SL-YEO-S has a cup diameter of 28.72 mm / 1.1307 in compared to 25.25 mm / 0.9941 in on the Yamaha SL-48S-GP — a difference of 3.47 mm / 0.1366 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Yamaha SL-YEO-S has a deep cup while the Yamaha SL-48S-GP has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
The Yamaha SL-YEO-S has a wider throat (8.00 mm / 0.3150 in vs 6.62 mm / 0.2606 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.