Bach 6½AL (small shank) vs Kelly 5G-EU-SS
the Kelly 5G-EU-SS features a deeper cup.
Mouthpiece A
Bach 6½AL (small shank)
• Baritone / Euphonium
Cup diameter25.40 mm / 1.0000 in
Cup depthDeep
Rim width—
Throat diameter6.63 mm / 0.2610 in
Backbore—
Finish—
Material—
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
vs
Mouthpiece B
Kelly 5G-EU-SS
• Baritone / Euphonium
GeneralCup diameter25.40 mm / 1.0000 in
Cup depth
Rim width—
Throat diameter—
BackboreL
Finish—
Material316 Surgical Stainless Steel
Best suited for
Orchestral playing — large cup for full, dark tone
Euphonium general use
Cup Diameter
Both mouthpieces have virtually identical cup diameters at 25.40 mm / 1.0000 in.
Cup Depth
The Kelly 5G-EU-SS has a — cup while the Bach 6½AL (small shank) has a deep cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Bach 6½AL (small shank) is described as unspecified, and the Kelly 5G-EU-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.