What Does the Backbore Do?
The backbore plays an important role in regulating resistance and shaping the way your trumpet responds and sounds. Selecting the right backbore is ultimately about finding a balance between the instrument’s resistance and the way you naturally produce sound.
Fine-tuning resistance through the backbore is closely connected to your physiology and type of playing you do. For example your air capacity, coordination of the chest, back, and abdominal muscles, and the elasticity of your lips. Your musical needs such as volume, tone color, breadth of sound, intensity and technical efficiency all influence what backbore will work best for you.
Every backbore you try will perform a little differently in each of these areas as your trumpet and choice of cup style set the stage.
A good way to choose the correct backbore is to not change your natural approach to playing but find one that comes to you!
Things to think about when choosing a backbore
Backbores are the internal passage behind the mouthpiece’s throat, leading toward the trumpet’s/brass instruments leadpipe. Its size and shape influence:
• Resistance – How much air resistance you feel while playing.
• Response – How quickly notes speak, especially in the upper register.
• Tone – Often affecting brightness vs. warmth and the overall “spread” of the sound.
• Airflow – A larger backbore generally allows more air through; a smaller one tends to provide more resistance.
• Endurance – The right amount of resistance can make it easier to play efficiently for long periods.
• Intonation – Changing the airflow characteristics can affect how certain notes center and how easily you adjust pitch.
• Register flexibility – Some backbores make low notes feel more open, while others can make upper-register playing feel more focused.
Gap
Trumpet players often want to adjust the gap between the backbore and the leadpipe. You can use a GapChek to check the gap. Many trumpeters buy Reeves Sleeves which come in different sizes and help adjust gap. You can try different sleeves to see which one helps your trumpet response and sound. KT Custom Mouthpiece can cut your backbores for sleeves.