Curry 7F vs Yamaha HR-30D4
The Yamaha HR-30D4 has a wider cup diameter, the Yamaha HR-30D4 features a deeper cup.
Cup Diameter
The Yamaha HR-30D4 has a cup diameter of 17.08 mm / 0.6724 in compared to 17.02 mm / 0.6700 in on the Curry 7F — a difference of 0.06 mm / 0.0024 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Yamaha HR-30D4 has a deep cup while the Curry 7F has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
Throat diameters are essentially identical at 4.50 mm / 0.1770 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.