Bach 1¼G vs Conn Imp. Precision 5
Both mouthpieces share similar core dimensions — the differences are in the details.
Mouthpiece A
Bach 1¼G
• Trombone
Cup diameter27.50 mm / 1.0827 in
Cup depthVery deep
Rim width—
Throat diameter7.01 mm / 0.2760 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
Conn Imp. Precision 5
• Trombone
GeneralCup diameter—
Cup depthVery deep
Rim width—
Throat diameter—
Backbore—
Finish—
MaterialSilver-plated brass
Best suited for
Connstellation-equipped tenor trombone
Designed for Connstellation 24I/25I
Cup Depth
Both mouthpieces share a very deep cup depth, so the sound character from depth alone will be very similar.
Material
The Bach 1¼G is described as unspecified, and the Conn Imp. Precision 5 as Silver-plated brass. 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.