What's The Best Backbore to Match My Top?
Backbore Size - Small, Medium, Medium Large
- We make one piece backbores in 3 sizes.
- Some cup depths tend to work better with certain backbores, but to a large extent this is also a matter of personal preference.
- A good guide to what backbore to choose for a modular mouthpiece is the backbore size used on one piece models.
Small
- Slightly larger than Schilke A backbore
- Produces a compact lead sound with good upper register support
- Works well with ES, LV, S cups
Medium
- Similar to Schilke B, Warburton 7*
- Well matched to MV cups, or MDV when a more compact sound and better upper register support desired
- Medium broad sound suitable for a wide variety of playing situations, very versatile
- Works well with MV cups
Medium Large
- Similar to Bach 10, Warburton 8, 8*
- Well matched to MDV and RT cups
- Broad, resonant sound
- Suitable for orchestra, solo, quintet
- Best choice for MDV, RT cups
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- ES, LV, S Cups - Small (S) backbore
- MV Cups - Medium (M) backbore
- MDV, RT Cups - Medium Large (ML) backbore
Backbore Length - Bb and C
Backbores are available in Bb trumpet and C trumpet lengths.
Using the shorter C trumpet shank shortens the backbore, and therefor the mouthpiece length by about .25 inches
What Are the Advantages of a C-Length Backbore?
Bb-length backbores can be used on a C trumpet, but a C-length backbore offers several important advantages:
Shorter overall length
Our Medium Large C-length backbore shortens the mouthpiece by approximately 0.25 inches, making it similar in length to a Monette Bb mouthpiece.
Improved pitch in the middle register
The shorter length raises the pitch of the 5th partial, improving the tuning of:
• 4th space E
• C, D, and Eb
Most players find these notes sit more securely in tune, reducing the need for alternate fingerings.
More open, resonant feel
Produces a slightly more open blow and a broader, more resonant sound.
Slightly looser slotting
Slotting is a bit less defined, which many players prefer for added flexibility.
Potential Trade-Off
On some instruments, the shorter backbore can push top-of-staff G slightly sharp.
This is instrument-dependent, but can be a concern for players who are already sharp in that register.
The Solution
This is exactly where the Wedge Variable Length Backbore (VLB) becomes valuable—allowing you to fine-tune backbore length to optimize pitch without introducing unwanted sharpness.
Variable Length Backbore (VLB) - Small to Large
Wedge Adjustable Backbores (VLB) – Overview & Use
Backbore length has a major influence on how a mouthpiece slots. Most noticeably, it affects the pitch of the 5th partial, which in turn impacts the tuning of 4th space E and related notes such as Eb and D. These notes tend to run flat on Bb trumpets—and often even flatter on C or higher-pitched instruments.
This is why many manufacturers offer shorter backbores, particularly for C trumpet, though they are also used on Bb horns.
Cup depth also influences pitch relationships between notes. To compensate, some designs pair deeper cups with shorter backbores to maintain balance.
The Challenge
Shortening the backbore raises the pitch of the 5th partial—but it can also affect the 6th partial, pushing top-of-staff G sharp if the backbore is too short or not well matched to the cup.
- A slightly flat E can usually be adjusted
- A sharp G is much harder to manage
This trade-off has traditionally forced players to compromise.
The Solution
Now you don’t have to.
The Wedge Adjustable Backbore (VLB) allows you to precisely fine-tune backbore length—so you can optimize 5th partial pitch without making G uncomfortably sharp.
How It Works
- The backbore features a central core that determines size (Small → Large)
- The threaded shank adjusts length across a wide range—from longer than typical Bb backbores to shorter than most C backbores
- A knurled locking collar secures the setting at repeatable reference points
Setup Instructions
- Assemble your mouthpiece with your chosen top and VLB backbore
- Play and evaluate pitch and slotting
- Focus on key notes:
- 4th space E
- Top-of-staff G
- Adjust backbore length incrementally
- Lock in the position once you find the best balance
After adjustment, install your chosen sleeve (regular or heavy) over the mechanism before attaching the top.
Backbore Sizes
Small Backbore
- Best with: ES, LV, S cups
- Feel: Focused, efficient, strong upper register support
- Comparable to: Slightly larger than Schilke A; similar to Warburton 4–5 or Pickett 10-4
Medium Backbore
- Best with: MV, MDV
- Feel: Balanced response, versatile across registers
- Comparable to: Warburton 6–7 or Pickett 10-3
Medium Large (ML)
- Best with: MDV, RT (also works well with MV)
- Feel: Broader sound, slightly less upper register support
- Ideal for: Orchestral playing
- Comparable to: Bach 10, Warburton 8–10, Pickett 10-2
Large Backbore
- Best with: MDV, RT
- Feel: Broadest sound, most open response
Throat Options
- Available with #27 or #25 throats
Note:
At the shortest settings, the VLB can feel tighter than a fixed C backbore.
If you plan to use shorter settings regularly, consider choosing one size larger than your usual backbore.
Sleeve Options
- Heavy Sleeve
- Slightly reduces bright overtones
- Improves slotting stability
- Designed for Wedge tops
- Regular Sleeve
- Compatible with Wedge tops and most standard 3/8-40 threaded tops
- (Warburton, ACB, Pickett, etc.)
Shank Options
Standard Shank
- OD: 0.385" (industry standard, ±0.001 variation typical)
Variable Gap Shanks (optional)
Fine-tune response and feel by adjusting mouthpiece gap:
| Size | OD (inches) | Effect |
| 1 | 0.397 | Largest gap |
| 2 | 0.394 | |
| 3 | 0.391 | |
| 4 | 0.388 | |
| 5 | 0.385 | Standard |
| 6 | 0.382 | |
| 7 | 0.379 | Smallest gap |
- Available individually or in sets of three (10% discount)
Why It Matters
Combining adjustable backbore length with variable gap shanks gives you unprecedented control:
- Dial in pitch accuracy across partials
- Optimize slotting for your specific horn
- Match performance precisely to your cup and playing style
Result: A mouthpiece that is truly customized to you—not a compromise.