Bach 1¼G vs Kelly BEAST-LS-SS
The Kelly BEAST-LS-SS has a wider cup diameter, the Kelly BEAST-LS-SS features a deeper cup.
Cup Diameter
The Kelly BEAST-LS-SS has a cup diameter of 28.70 mm / 1.1299 in compared to 27.50 mm / 1.0827 in on the Bach 1¼G — a difference of 1.20 mm / 0.0472 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Kelly BEAST-LS-SS has a — cup while the Bach 1¼G has a very deep cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Bach 1¼G is described as unspecified, and the Kelly BEAST-LS-SS as 316 Surgical Stainless Steel. 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.