Bach 17 vs Bach 18
Both mouthpieces share similar core dimensions — the differences are in the details.
Mouthpiece A
Bach 17
• Trumpet
Cup diameter15.10 mm / 0.5945 in
Cup depthVery deep
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
vs
Mouthpiece B
Bach 18
• Trumpet
Cup diameter15.10 mm / 0.5945 in
Cup depthVery deep
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
Cup Diameter
Both mouthpieces have virtually identical cup diameters at 15.10 mm / 0.5945 in.
Cup Depth
Both mouthpieces share a very deep cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
Throat diameters are essentially identical at 3.66 mm / 0.1441 in, so resistance feel will be comparable.
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.