Kelly 5C vs Monette Unity D2
The Monette Unity D2 has a wider cup diameter, the Kelly 5C features a deeper cup, the Kelly 5C has a larger throat opening.
Cup Diameter
The Monette Unity D2 has a cup diameter of 17.00 mm compared to 16.76 mm on the Kelly 5C — a difference of +0.24 mm. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Kelly 5C has a very deep cup while the Monette Unity D2 has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
The Kelly 5C has a wider throat (3.80 mm vs 3.66 mm). A wider throat allows more air through, increasing volume and projection but reducing resistance.
Material
The Kelly 5C is described as Lexan polycarbonate, and the Monette Unity D2 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.