Bach 17D vs Bach 4C
The Bach 4C has a wider cup diameter.
Mouthpiece A
Bach 17D
• Baritone / Euphonium
Cup diameter24.20 mm / 0.9528 in
Cup depthShallow
Rim width—
Throat diameter5.85 mm / 0.2303 in
Backbore—
Finish—
Material—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 4C
• Baritone / Euphonium
Cup diameter25.75 mm / 1.0138 in
Cup depthShallow
Rim width—
Throat diameter5.85 mm / 0.2303 in
Backbore—
Finish—
Material—
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Bach 4C has a cup diameter of 25.75 mm / 1.0138 in compared to 24.20 mm / 0.9528 in on the Bach 17D — a difference of 1.55 mm / 0.0610 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a shallow cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
Throat diameters are essentially identical at 5.85 mm / 0.2303 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.