Bach 10½C vs Monette Vintage B4L S1
The Monette Vintage B4L S1 has a wider cup diameter, the Bach 10½C features a deeper cup.
Cup Diameter
The Monette Vintage B4L S1 has a cup diameter of 16.20 mm / 0.6378 in compared to 15.90 mm / 0.6260 in on the Bach 10½C — a difference of 0.30 mm / 0.0118 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 10½C has a medium cup while the Monette Vintage B4L S1 has a very shallow 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 3.66 mm / 0.1441 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.