Bach Trumpet Mouthpiece Guide
From student starters to principal-chair orchestral models — the complete dimensional reference for every Bach trumpet and cornet mouthpiece, with the Big Three explained.
Decoding the Bach Number–Letter System
A Bach model name encodes exactly two parameters: a number for rim size, and a letter for cup depth. Nothing more. Once you understand the scale, any Bach designation becomes immediately legible.
Rim diameter — higher number = smaller inner rim. The scale is not linear: jumps between consecutive numbers vary from 0.2 mm to 0.8 mm. 1 is the largest, 20 is the smallest. No conversion formula exists — use the published dimension table.
Cup depth. No letter = deep bowl. C = medium (the most common suffix). E = shallow. Intermediate: B (medium-deep), D (medium-shallow), SV (shallow V-shaped bowl). W = wide rim variant.
7 = rim inner diameter 16.20 mm (0.638″). C = medium cup depth. Combined: a medium-sized rim with a balanced, versatile cup. The world's best-selling trumpet mouthpiece for over 70 years.
The "C" default rule: When a teacher says "play on a Bach 3," they almost always mean "Bach 3C." The bare number without a letter designates the deep cup variant — rarely appropriate for most players. Always clarify the suffix.
Bach 3C · 5C · 7C
Three models define the professional conversation about trumpet mouthpieces worldwide. Understanding why each exists tells you everything about how to choose between them.
Bach 3C
The largest of the Big Three. A 3C demands more air and embouchure development but rewards the player with a full, singing tone ideal for orchestral principal work, brass quintet, and large ensemble playing. Many conservatory-trained players settle on 3C permanently.
Orchestral principals, advanced students transitioning from 5C, euphonium-to-trumpet doublers.
Bach 5C
The true middle ground. The 5C rim sits between 3C and 7C and is the default recommendation across most of Europe and Asia. Excellent for players who need full tone production but want slightly less effort than a 3C. Often described as "the 3C that plays itself."
Advanced students, section players, orchestral players outside the principal chair, jazz players wanting warmth.
Bach 7C
The 7C is the entry point for most players and never truly leaves. Its slightly smaller rim aids upper register access, and the medium cup is forgiving enough for nearly any style. Sold in millions. Used by amateurs and seasoned players alike. Often the "reference" when teachers discuss switching.
Students, beginners, commercial players, lead players who grew up on 7C and adapted. Also used in piccolo settings.
Bach Artisan — The Modern Premium Line
Introduced as Bach's response to boutique competitors (Monette, GR, Warburton), the Artisan series features hand-finished cups, tighter quality control tolerances, and updated cup geometry while retaining the classic Bach numbering system.
Artisan cups are machined to ±0.01 mm tolerances vs. standard Bach's ±0.05 mm. The difference is felt in consistency: back-to-back models play identically rather than with the traditional "lottery" variation in Standard Series.
The Artisan standard rim has a slightly narrower inner edge and a more gradual cup-to-throat transition. Players describe more centered slotting and faster response compared to the same number in Standard Series.
An Artisan 3C is NOT a direct substitute for a Standard 3C. The cup geometry and throat transition differ noticeably. Try before committing if you've spent years on a Standard Bach.
Artisan availability: Not all Bach numbers are available in Artisan. The Artisan line focuses on 1C, 3C, 5C, 7C, and 10.5C — the most commercially important models. Obscure numbers (e.g. 6, 11, 12) remain Standard Series only.
Published Dimension Table
Inner rim diameter measurements from official Bach catalogs. Cup depth descriptions reflect Bach's standard terminology.
| Model | Rim Diameter (mm) | Rim Diameter (in) | Cup Depth | Primary Character |
|---|---|---|---|---|
| 1 | 17.00 | 0.670″ | Deep | Large orchestral volume; massive fundamental |
| 1C | 17.00 | 0.670″ | Medium | Large rim, balanced cup — lead orchestral |
| 1.5C | 16.84 | 0.663″ | Medium | Between 1C and 2C; full, centered tone |
| 2C | 16.84 | 0.663″ | Medium | Dark, full orchestral — less common |
| 3 | 17.00 | 0.668″ | Deep | Large orchestral — broad and open |
| 3C | 17.00 | 0.668″ | Medium | The Big Three — professional balanced all-rounder |
| 5C | 16.84 | 0.663″ | Medium | The Big Three — slightly smaller, popular worldwide |
| 5SV | 16.84 | 0.663″ | Medium | Shallow V-cup variant of 5C; brighter tone |
| 6 | 16.84 | 0.663″ | Deep | Old-style deep cup; mellow orchestral |
| 7C | 16.20 | 0.638″ | Medium | The Big Three — student & crossover; most popular single model |
| 7E | 16.20 | 0.638″ | Shallow | Lead/commercial variant of 7C |
| 10.5C | 15.90 | 0.626″ | Medium | Compact rim; upper register ease for lead/commercial |
| 10.5SV | 15.90 | 0.626″ | Shallow V | Very bright lead variant |
| 11 | 15.90 | 0.626″ | Deep | Orchestral piccolo/high register specialist |
| 12 | 15.24 | 0.600″ | Medium | Very narrow; extreme high register / piccolo trumpet |
| 24AW | 16.20 | 0.638″ | Shallow A | Wide rim + shallow A cup; lead/commercial |
Source: Vincent Bach / Conn-Selmer official catalog data. Measurements are inner rim diameter at the playing surface.
Bach → Other Brands
Because Bach is the reference standard, most manufacturers publish "Bach equivalent" specs. These are approximate — rim geometry and cup shape vary even when rim diameter matches.
| Brand | ≈ Bach 1C | ≈ Bach 3C | ≈ Bach 5C | ≈ Bach 7C | ≈ Bach 10.5C |
|---|---|---|---|---|---|
| Schilke | 18 / 17 | 16 / 15 | 14 / 13 | 11 | 6 / 7B |
| GR Technologies | 67 Series | 66 Series | 65 Series | 64 Series | 63 Series |
| Warburton | 2 | 3 / 4 | 5 | 6 | 7 |
| Bob Reeves | 43.5 | 43 | 42 | 41 | 40 |
| Wedge | 68MDV | 66MV | 65MV | 64MV | 63MV |
| Marcinkiewicz | Model 1 | Model 3 | Model 3.5 | Model 4 / 5 | Model 6 |
| Denis Wick | 2 | 3 / 3B | 4 | 5 | 6 / 7 |
Approximate equivalencies based on published rim diameter data. Cup shape and throat dimensions vary — always audition before switching.