Conn Precision 3 vs Kelly 6-1/2AL-LS-SS
the Conn Precision 3 features a deeper cup.
Mouthpiece A
Conn Precision 3
• Trombone
GeneralCup diameter—
Cup depth
Rim width—
Throat diameter—
Backbore—
Finish—
MaterialSilver-plated brass
Best suited for
Musicians with large lips; all kinds of band work
Full round tone; ideal for large lips
vs
Mouthpiece B
Kelly 6-1/2AL-LS-SS
• Trombone
GeneralCup diameter25.15 mm / 0.9902 in
Cup depthVery deep
Rim width—
Throat diameter—
BackboreM
Finish—
Material316 Surgical Stainless Steel
Best suited for
Orchestral playing — large cup for full, dark tone
Standard large-shank trombone / euphonium
Cup Depth
The Conn Precision 3 has a — cup while the Kelly 6-1/2AL-LS-SS has a very deep cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Conn Precision 3 is described as Silver-plated brass, 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?
Both mouthpieces are categorized as "General" — the physical dimensions above will determine which suits your embouchure and playing style better.