Bach 1¼C vs Monette B5L S1
The Bach 1¼C has a wider cup diameter, the Bach 1¼C features a deeper cup.
Cup Diameter
The Bach 1¼C has a cup diameter of 17.00 mm / 0.6693 in compared to 16.25 mm / 0.6398 in on the Monette B5L S1 — a difference of 0.75 mm / 0.0295 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 1¼C has a medium cup while the Monette B5L 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.