Is the Yamaha 14D4 really the closest thing to a Bach 3C?

For most players, yes. The D cup in Yamaha falls in the range that practically matches the C cup depth of Bach. The 14C4 tends to play slightly shallower than a Bach 3C. Try the 14D4 first when looking for a Bach 3C equivalent.

Why does Yamaha use 4 as their standard rim contour when Schilke uses 3?

Different design choices. Yamaha's default rim is slightly flatter than Schilke's standard. Neither is objectively better — it is a design preference that some players prefer and others do not.

The Yamaha mouthpiece I bought says TR-14D4 on the box but just 14D4 on the mouthpiece. Are they the same?

Yes. The TR prefix is sometimes omitted on the physical engraving while appearing in the full product name. Same mouthpiece.

Can I use a Yamaha CN (cornet) mouthpiece on a trumpet?

The cornet shank sits differently in a trumpet receiver than a trumpet shank does. The fit is imprecise, affecting intonation and response. Use instrument-appropriate shanks for regular playing.

Yamaha Trumpet Mouthpiece Numbers Explained — The Complete Decoder

Yamaha mouthpiece numbers follow a logic that's different from both Bach and Schilke — and they contain two traps that catch players constantly. The most dangerous one: the cup depth letters run in the opposite direction from Bach, meaning Yamaha A is the shallowest cup (lead territory) while Bach A is the deepest cup (orchestral territory).

Get that backwards once and you'll buy the complete opposite of what you intended. This guide decodes the full Yamaha system and prevents that mistake.

The Two Yamaha Traps

Before the full decoder, two critical warnings:

Trap 1: Yamaha cup letters are reversed from Bach.
Yamaha A = shallow. Bach A = deep. The only letter that means the same thing in both systems is C (standard). Every other letter is reversed.

Trap 2: Yamaha's number scale is completely different from Bach and Schilke.
Yamaha uses a scale from roughly 5 to 68. These numbers have no relationship to Bach or Schilke numbers. A Yamaha 14 is not the same as a Bach 14 (which doesn't exist) or a Schilke 14 (which is a specific model).

With those warnings in place, here's the complete decoder.

The Yamaha Model Code Structure

  TR  -  14   D   4
   │      │   │   │
   │      │   │   └── Rim contour (1=roundest, 4=semi-flat, 5=flattest)
   │      │   └─────── Cup depth (A=shallowest, C=standard, E=deepest — OPPOSITE TO BACH)
   │      └──────────── Inner diameter number (higher = broader)
   └─────────────────── Instrument prefix (TR=trumpet, CN=cornet, FL=flugelhorn)

The TR prefix appears in official model listings but is often dropped in casual reference. "Yamaha 14D4" and "Yamaha TR-14D4" are the same mouthpiece.

The Inner Diameter Number

Yamaha uses a scale roughly from 5 to 68 where higher numbers mean broader rims. The scale runs in the intuitive direction — higher = bigger — which differs from Bach's counterintuitive lower = bigger.

Yamaha number	Rim inner diameter (approx.)	Bach equivalent area
7	~14.60mm	Below standard Bach range
9	~15.10mm	Bach 12 area
11	~16.20mm	Bach 7C
13	~16.48mm	Bach 5C
14	~16.76mm	Bach 3C area
16	~16.84mm	Bach 1.5C area
17	~17.00mm	Bach 1C area

The most commonly used Yamaha numbers:
- 11 = Bach 7C area
- 14 = Bach 3C area
- 16 = Bach 1.5C area

The Cup Depth Letter — The Critical Reversal

This is where Yamaha catches players. Study this table carefully:

Yamaha letter	Cup depth	Bach equivalent letter	Tone character
A	Shallowest	Roughly Bach E	Lead / commercial — bright, focused
B	Medium-shallow	Roughly Bach D	Brighter, more commercial
C	Standard	Roughly Bach C	All-around, balanced
D	Medium-deep	Roughly Bach B	Warmer, fuller
E	Deepest	Roughly Bach A	Orchestral, very warm

The practical consequences:

A Yamaha 14A4 = medium-large rim + shallowest cup = lead mouthpiece. If you read the A as Bach convention, you'd expect deep orchestral. It's the opposite.

A Yamaha 14D4 = medium-large rim + medium-deep cup = the closest Yamaha equivalent to a Bach 3C. The D in Yamaha is approximately equivalent to C in Bach for most practical purposes.

A Yamaha 16C4 = large rim + standard cup = orchestral equivalent to Bach 1.5C.

The Rim Contour Number

The third character (a number from 1 to 5) indicates rim contour, using the same scale as Schilke:

Number	Rim contour	Feel
1	Roundest	Softest, most comfortable
2	Semi-round	Comfortable with slight definition
3	Standard	Middle point
4	Semi-flat	More precise placement reference
5	Flattest	Maximum precision

Most standard Yamaha models use contour 4 — semi-flat. This is slightly flatter than Bach's standard rim. Players switching from Bach to Yamaha sometimes notice this difference — the Yamaha rim feels slightly more defined at the inner edge.

The Bobby Shew Signature Models

Yamaha produces Bobby Shew signature mouthpieces that use descriptive names rather than the standard number-letter-number code:

Bobby Shew Jazz: Medium cup, medium-wide rim. For mainstream jazz playing. Warm tone with presence.

Bobby Shew Lead: Shallow cup, medium rim. For lead trumpet. An alternative to the Schilke 14A4a in lead territory.

These are the most widely played Yamaha mouthpieces beyond the standard catalog. Players looking for Yamaha's offering in mainstream jazz or lead categories often start here.

The TR / CN / FL Prefix System

Yamaha distinguishes instrument types with a prefix:
- TR = Trumpet (Bb and C)
- CN = Cornet
- FL = Flugelhorn

A Yamaha FL-14D4 is a flugelhorn mouthpiece with rim dimensions in the 14 area and a medium-deep cup — appropriate for a trumpet player in the Bach 3C/Schilke 14 range who is doubling on flugelhorn. The FL prefix means it has the correct flugelhorn shank and cup geometry.

This prefix system is one of the more player-friendly aspects of Yamaha's naming — you always know which instrument a mouthpiece is for.

Yamaha to Bach Translation

You play	Yamaha equivalent	Notes
Bach 7C	Yamaha 11C4	Very close match
Bach 5C	Yamaha 13C4	Close
Bach 3C	Yamaha 14D4	D in Yamaha ≈ C in Bach in practice
Bach 1.5C	Yamaha 16C4	Close match
Bach 3E (lead)	Yamaha 14A4	Remember: Yamaha A = shallow
Bach 1C	Yamaha 17C4	Close match

Why 14D4 ≈ Bach 3C (not 14C4): The Yamaha D cup is slightly deeper than what Yamaha calls C. In practice, the 14D4's actual depth falls in the range most players experience as equivalent to a Bach C cup. The 14C4 tends to play slightly shallower than a Bach 3C for many players.

For precise mm-based comparison, use the Cross-Brand Comparator rather than relying on letter equivalence.

Common Yamaha Models Decoded

Model	Rim	Cup	Contour	What it is
11C4	Bach 7 area	Standard	Semi-flat	All-around beginner/intermediate
14D4	Bach 3 area	Med-deep (≈Bach C)	Semi-flat	All-around workhorse — most used Yamaha
14A4	Bach 3 area	Shallow (lead)	Semi-flat	Lead mouthpiece
16C4	Bach 1.5 area	Standard	Semi-flat	Orchestral standard
16B4	Bach 1.5 area	Med-shallow	Semi-flat	Orchestral, slightly brighter
Bobby Shew Lead	Medium	Shallow	—	Lead, widely used
Bobby Shew Jazz	Medium-large	Medium	—	Jazz mainstream

What to Do Next

Decode any Yamaha model instantly:
→ Naming Decoder

Find Yamaha equivalents for your current mouthpiece:
→ Cross-Brand Comparator

Read the full Yamaha brand guide:
→ Yamaha Brand Guide

Read all the naming systems together:
→ Trumpet Mouthpiece Sizes and Numbers Explained