Bach 18 vs Kelly 6-1/2AL-LS-SS
The Kelly 6-1/2AL-LS-SS has a wider cup diameter, the Kelly 6-1/2AL-LS-SS features a deeper cup.
Cup Diameter
The Kelly 6-1/2AL-LS-SS has a cup diameter of 25.15 mm compared to 24.20 mm on the Bach 18 — a difference of +0.95 mm. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Kelly 6-1/2AL-LS-SS has a very deep cup while the Bach 18 has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Bach 18 is described as unspecified, and the Kelly 6-1/2AL-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.
Compare Bach 18 with others
Compare Kelly 6-1/2AL-LS-SS with others
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