Detail 01
14 rim size
Roughly a Bach 3C rim diameter. Wider than a 7C, which gives more lip surface and endurance on long sessions.

Independent shopping perspective
Yamaha's 14B4 standard trumpet mouthpiece. Medium rim with a shallower B cup, aimed at players who want easier upper register than a stock 7C.

Strong match
Consider the trade-offs
What matters in use
Catalog numbers tell only part of the story. These are the details most likely to change how this product feels, sounds, or fits into a setup.
Detail 01
Roughly a Bach 3C rim diameter. Wider than a 7C, which gives more lip surface and endurance on long sessions.
Detail 02
Shallower than the common C cup. Brighter tone, less air needed up high, less body in the low register.
Detail 03
Yamaha's standard backbore across the line. Keeps resistance even so the horn feels normal, not tight or wide open.
Detail 04
If you already play a 3C, the rim will feel familiar; the cup will feel shallower and brighter.
Detail 05
Machine-cut to a fixed spec, so a replacement in five years plays identically to this one.
Final check
Product questions
Straight answers to the questions shoppers most often ask about this product.
The 14B4 has a wider rim and shallower cup. Expect easier high notes and a brighter sound, with less depth below the staff than a 7C.
The rim is close to a Bach 3C. The cup is shallower than any C cup, so the overall feel sits between a 3C rim and a lead piece.
No. Cornet receivers take a shorter, narrower shank. This is cut for trumpet only.
Only if you already have a solid embouchure and want more high range. Developing players usually do better staying on a deeper C cup first.
Reference
The complete catalog record, organized around the decisions musicians make when comparing gear.