Schilke mouthpiece numbers confuse almost every player who encounters them for the first time — not because the system is poorly designed, but because it runs in the opposite direction from Bach. If you understand Bach numbers, your first instinct about Schilke is wrong.
This guide decodes the complete Schilke system: every character in the model name, what it means, and how it relates to Bach equivalents. By the end you'll be able to look at any Schilke model and know exactly what it is.
The Most Important Thing to Know First
Schilke numbers run opposite to Bach. Lower Schilke number = smaller diameter.
In Bach: lower number = larger mouthpiece (Bach 1 is bigger than Bach 7).
In Schilke: lower number = smaller mouthpiece (Schilke 6 is smaller than Schilke 16).
This single fact is the source of almost all Schilke confusion. A player who picks up a Schilke 3 thinking it's similar to a Bach 3 ends up on something dramatically smaller. A player who grabs a Schilke 14 without knowing the system may be surprised to find it's in the Bach 3C range.
Keep this inversion in mind throughout everything below.
The Four-Part Schilke Code
A complete Schilke model name has four components. Most catalog models only show some of them — the rest are assumed standard.
14 A 4 a
│ │ │ │
│ │ │ └── Backbore (a=tight through z=extra-tight)
│ │ └───────── Rim contour (1=roundest through 5=flattest)
│ └─────────────── Cup volume (A=small/shallow through E=large/deep)
└───────────────────── Cup diameter number (lower = smaller)
When a model shows only a number — like "Schilke 14" — it means all other parameters are standard: C cup volume, 3 rim contour, c backbore. The full code is 14C3c, abbreviated to 14.
Component 1: The Cup Diameter Number
The number refers to the cup diameter — the rim inner diameter. Lower = smaller. Higher = larger.
| Schilke number | Rim inner diameter (approx.) | Bach equivalent area |
|---|---|---|
| 6 | ~14.30mm | Much smaller than any standard Bach |
| 7 | ~14.60mm | Below Bach 12 |
| 10 | ~15.40mm | Bach 12 area |
| 11 | ~16.20mm | Bach 7C |
| 12 | ~16.30mm | Between Bach 7 and 5 |
| 13 | ~16.48mm | Bach 5C |
| 14 | ~16.76mm | Bach 3C area |
| 15 | ~16.84mm | Between Bach 3 and 1.5 |
| 16 | ~16.84mm | Bach 1.5C area |
| 17 | ~17.00mm | Bach 1C area |
| 18 | ~17.15mm | Larger than Bach 1C |
| 21 | ~17.40mm | Very large — specialist use |
The most commonly used Schilke numbers in typical trumpet playing:
- 11 = Bach 7C area (beginner/intermediate standard)
- 13 = Bach 5C area
- 14 = Bach 3C area (the all-around workhorse)
- 16 = Bach 1.5C area (orchestral standard)
Component 2: The Cup Volume Letter
The letter indicates cup volume — a combination of cup depth and shape that Schilke characterizes as a volume rather than a simple depth measurement.
| Letter | Cup volume | Approximate Bach cup equivalent |
|---|---|---|
| A | Small / shallow | Between Bach D and E |
| B | Medium-small | Roughly Bach D |
| C | Standard | Roughly Bach C |
| D | Medium-large | Roughly Bach B |
| E | Large / deep | Roughly Bach A |
Critical note: Schilke's C is the standard middle, just like Bach's C. But the direction runs opposite — Schilke A is small/shallow (same direction as Bach A = large), wait — actually both A ends are opposite ends of the spectrum. Let me clarify:
In Bach: A = deepest, F = shallowest.
In Schilke: A = smallest/shallowest, E = largest/deepest.
So Schilke A and Bach A are both at the "A end" of their respective scales — but Bach A means deepest and Schilke A means shallowest. They're at opposite ends acoustically.
Practical translation:
- Schilke A cup = lead/commercial territory (shallowest)
- Schilke C cup = standard all-around (medium)
- Schilke E cup = warm, deep orchestral (deepest)
Component 3: The Rim Contour Number
The second number in the full code indicates the cross-sectional shape of the rim.
| Number | Rim contour | Playing feel |
|---|---|---|
| 1 | Roundest | Softest, most comfortable for long sessions |
| 2 | Semi-round | Comfortable with slight definition |
| 3 | Standard | Default — appropriate for most players |
| 4 | Semi-flat | More precise embouchure placement reference |
| 5 | Flattest | Maximum precision at some comfort trade-off |
The standard rim (3) appears in most catalog models. The semi-flat (4) appears in the famous 14A4a — that contour is part of the lead mouthpiece's design, providing a precise placement reference for consistent high note production.
Most players who aren't specifically seeking a flatter rim should start with the standard (3) contour.
Component 4: The Backbore Letter
The final letter is Schilke's most thoroughly documented component — they publish a complete backbore system that no other major manufacturer matches.
| Letter | Backbore | Effect |
|---|---|---|
| a | Tight | Bright tone, upper register support, more resistance |
| b | Semi-tight | Between tight and standard |
| c | Standard | Balanced — the default |
| d | Medium large | Darker tone, less resistance |
| x | Large | For piccolo trumpet specifically |
| z | Extra-tight | Maximum resistance and focus |
Standard c backbore is implied when no backbore letter appears. The a backbore (tight) is explicitly noted in the 14A4a because it's essential to that mouthpiece's lead characteristics.
For detailed explanation of what each backbore does, see Backbore Explained.
The Schilke 14A4a Fully Decoded
The most famous Schilke model — decoded character by character:
- 14 → Cup diameter: medium-large (~16.76mm), Bach 3C rim area
- A → Cup volume: small/shallow — lead territory
- 4 → Rim contour: semi-flat — precise placement reference
- a → Backbore: tight — upper register support, brightness
Combined: medium-large rim + shallow cup + semi-flat rim + tight backbore. Every parameter optimized for lead trumpet. The standard by which all lead mouthpieces are measured.
The Most Common Schilke Models at a Glance
| Model | Full code | What it is | Bach equivalent |
|---|---|---|---|
| Schilke 11 | 11C3c | Medium-small rim, standard | Bach 7C |
| Schilke 13C | 13C3c | Medium rim, standard | Bach 5C |
| Schilke 14 | 14C3c | Medium-large rim, standard | Bach 3C |
| Schilke 14B | 14B3c | Medium-large rim, medium-small cup | Bach 3D (slightly brighter) |
| Schilke 14D | 14D3c | Medium-large rim, medium-large cup | Bach 3B (slightly warmer) |
| Schilke 14A4a | 14A4a | Lead — medium-large rim, shallow cup, semi-flat rim, tight backbore | Bach 3E area (but different backbore) |
| Schilke 16 | 16C3c | Large rim, standard | Bach 1.5C |
| Schilke 16C | 16C3c | Same as above — C is explicit | Bach 1.5C |
| Schilke 17 | 17C3c | Large rim, standard | Bach 1C |
Schilke vs. Bach: The Translation Rule
The key rule for translating between Bach and Schilke:
Bach rim number ↔ Schilke rim number: find the Schilke number whose measured diameter matches the Bach diameter — don't match the numbers directly.
Bach 3 ≠ Schilke 3. Bach 7 ≠ Schilke 7. The numbers share no relationship.
Instead:
- Bach 7C (16.20mm) → Schilke 11 (16.20mm) ✓
- Bach 3C (16.76mm) → Schilke 14 (16.76mm) ✓
- Bach 1.5C (16.84mm) → Schilke 16 (16.84mm) ✓
For any model not in this table, use the Cross-Brand Comparator — it matches by actual mm measurements rather than number equivalence.
What to Do Next
Decode any Schilke model instantly:
→ Naming Decoder
Find Schilke equivalents for your Bach mouthpiece:
→ Cross-Brand Comparator
Read the full Schilke brand guide:
→ Schilke Brand Guide
Read the complete naming systems guide:
→ Trumpet Mouthpiece Sizes and Numbers Explained
Related articles: Trumpet Mouthpiece Sizes and Numbers Explained · Schilke Brand Guide · Bach Numbers Explained · Cross-Brand Comparison Guide