Kelly 6-1/2AL vs Yamaha SL-48L-GP
The Yamaha SL-48L-GP has a wider cup diameter, the Kelly 6-1/2AL features a deeper cup.
Cup Diameter
The Yamaha SL-48L-GP has a cup diameter of 25.25 mm compared to 25.15 mm on the Kelly 6-1/2AL — a difference of +0.10 mm. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Kelly 6-1/2AL has a very deep cup while the Yamaha SL-48L-GP has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Kelly 6-1/2AL is described as Lexan polycarbonate, and the Yamaha SL-48L-GP as unspecified. Material affects mass, warmth, and how quickly the piece responds.
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.
Compare Kelly 6-1/2AL with others
Compare Yamaha SL-48L-GP with others
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