Trumpet Backbore Specifications

What's The Best Backbore to Match My Top?

In choosing a modular backbore you have to decide on a size (interior contour), weight, length, and material.

Click on each feature below to read more.

Backbore Size

  • We make backbores in 6 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.




  • Similar to Warburton KT*
  • Slightly more open lead backbore
  • Works well with ES, LV, S, M cups
  • Sound between S and M backbores




  • Similar to Schilke B, Warburton 7*
  • Well matched to M, MV cups, or MD and 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

Medium Large



  • Similar to Bach 10, Warburton 8, 8*.
  • Well matched to MD, MDV, RT, D cups
  • Broad, resonant sound
  • Suitable for orchestra, solo, quintet

Medium Large-Large



  • Similar to Bach 24, Warburton 9* to 10*
  • For use with MD, MDV, RT, D cups in an orchestral setting when an extra broad, resonant sound is desired




  • Larger than Bach 24, similar to Warburton 11 to 12*
  • Extra broad, resonant sound

The following combinations are used with our one piece mouthpieces because they work well for most players:

    • ES, LV, S Cups - Small (S) backbore
    • M, MV Cups - Medium (M) backbore
    • MD, MDV, RT, D Cups - Medium Large (ML) backbore

Our Medium Large-Large backbore (ML-L) and a Large (L) backbore are good options for players who want a broader sound with the deeper cups, or when using a C trumpet or rotary trumpet.

Backbore Weight

How do I choose the backbore weight?

The upper backbore section can be regular or heavy weight.

Heavy Weight Backbores

      • Choose a heavy weight backbore if you want a darker sound and more secure slotting.
      • Heavy weight backbores dampen some of the brighter overtones, producing a darker sound.
      • They add core to the sound, make slotting more secure, and reduce cracked notes.
      • Heavy backbores also make the mouthpiece slightly less responsive to soft articulation, although this is usually not an issue, since Wedge mouthpieces are more responsive than conventional designs.
      • You might notice that articulation is not as crisp when doing multiple tonguing with a heavy weight backbore.

Regular Weight Backbore

      • Regular weight backbores provide greater responsiveness, brilliance, and projection.
      • Choose a regular weight backbore if you want more brilliance and projection or cleaner articulation when multiple tonguing.

Backbore Length

Backbores are available in Bb trumpet and C trumpet lengths, determined by the length of the shank.

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 the C length backbore does offer certain advantages, such as:

    • Adding a C length shank to any Wedge backbore upper of the same size (S, M, ML, ML, L) makes it a C length backbore
    • C length backbores shorten the mouthpiece by about .25 inches, making it about the same length as a Monette Bb mouthpiece
    • The shorter length improves some of the pitch issues with some C trumpets by raising the pitch of the 4th space E and surrounding notes, reducing the need for alternate fingerings
    • Most players find that the C, D, Eb, and E are better in tune as a result
    • The shorter overall backbore length also make the mouthpiece have a slightly more open blow and broader, more resonant sound
    • Slotting is slightly less defined with the C length backbore
    • Some players find that the shorter backbore will also make the G at the top of the staff sharper than usual, which can be an issue on some instruments

Gap Adjusting Shanks

We also make shanks that are longer or shorter in 1/16 increments so that the mouthpiece gap can be increased or decreased by up to 1/8th inch.

Backbore Material

Silver backbores are the most popular option and offset gold tops nicely.
Gold backbores sound exactly like silver backbores but are preferred by those who like the look of an all gold mouthpiece. The shanks scratch easily and therefore gold backbores cannot be returned.
Stainless steel two piece backbores brighten the sound of any top they are used with. They make a stainless steel top project more than any other backbore, but the sound is difficult to darken and the mouthpiece can be prone to cracked notes. Stainless steel works extremely well with Delrin and acrylic plastic tops to make them sound almost the same as brass, but with a very fast response to soft articulation. Should I try a stainless steel backbore?

Advantages of Stainless Steel Backbores

    • Stainless steel backbores producer brighter sound with more projection compared to brass backbores
    • They are especially good at brightening the sound of plastic trumpet tops
    • They are more responsive than brass backbores

Disadvantages of Stainless Steel Backbores

    • Stainless steel backbores produce somewhat less core in the sound compared to brass
    • They are somewhat prone to causing more cracked notes compared to brass

Consider a heavy weight stainless steel as the best way to add more core and brightness to the sound of a plastic top.
Consider a regular weight stainless steel backbore if you want more projection and brilliance in your sound without using a shallower cup. Just be aware of the possibility of more cracked notes.