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Learn about the mouthpiece/trumpet annulus (gap)

  • The Gap is important. It is the best way to optimize the performance of your set-up.
  • The optimum gap is specific to the individual player, their mouthpiece, and their trumpet.
  • The optimum gap for each situation must be discovered through experimentation.

The information below will explain the what, how, and why of the gap based on our studies, experimentation, and experience.


ADJUSTING THE ANNULUS (GAP) IS PRIMARILY AN ACOUSTIC PHENOMENON.
IT HELPS DETERMINE THE LOCATION (RELATIVE PITCH) OF THE SLOTS.

Definition of The Annulus, or Gap

Receiver cut-away showing the "gap"

Receiver cut-away showing the “gap”

The “gap” affects the pitch center, or slot of every note on the trumpet. It does this by affecting the intonation of every note.

When the gap is not correct, you must compensate using your chops and air in an effort to make all the notes be in tune and sound as even in possible. This means you are working harder than you need to to play the instrument.

Signs of an incorrect gap:

  • Some notes are sharp and some notes are flat.
  • The upper register speaks well, while the low register speaks badly.
  • The low register speaks well, while the upper register is difficult.
  • All or some registers feel stuffy.
  • All or some registers feel too open.

The Annulus, or “Gap” as it is commonly referred to, is the space (chamber) between the end of a trumpet mouthpiece and the beginning of the leadpipe.

THE GAP IS THE MOST IMPORTANT DIMENSION THAT CAN EASILY BE ADJUSTED TO:

  • Make the upper register as easy as possible.
  • Improve your endurance.
  • Give you a full, resonant sound full of harmonics, or tonal colors.
  • Improve the low register.
  • Ensure the best intonation possible with your mouthpiece, your trumpet, and the way you play.
  • Give you more sound for less work.

The video below explains what the gap between the mouthpiece and leadpipe is.

The goal in adjusting the gap is to get the highest percentage of notes in tune with themselves.

The Function of The Gap

Different gaps using different Flex Couplers

When the gap is adjusted correctly, it allows you to use your air
in the most efficient manner possible.

Determining the Correct Gap

Using a Mouthpiece that is Converted for Couplers:

Start with the smallest number Coupler you have and play an F major scale from F in the staff to the octave above (just on top of the staff).

When you get to the top F listen and see if you have to:

  • Push up to be in tune.
  • Come down to be in tune.
  • Do nothing to be in tune (in other words, the pitch, or slot, is right where you want it to be).

Then try the next numbered Coupler you have and do the same thing. After you experiment a bit, you’ll start to hear and feel the gap adjustment.

The goal is to find the gap that gives you the best intonation.

Then use the one you find best in your routine. Don’t be afraid to change Couplers as you become more experienced with the gap effect.

The video below explains an easy way to determine the best gap for your mouthpiece, your trumpet, and the way you play using only an F Major Scale.

Using a solid shank mouthpiece – Follow the directions to the right:

FlexPaper

Start by playing an F major scale from F in the staff to the octave above (just on top of the staff).
When you get to the top F listen and see if you have to:

  • Push up to be in tune.
  • Come down to be in tune.
  • Do nothing to be in tune (in other words, the pitch, or slot, is right where you want it to be).

Then add a small piece of paper on the side of the shank as shown in the picture and play the scale again. If it improves you know you can benefit from a different gap.
If it gets worse or stays the same you know you are either:

  • At optimum Gap
  • Or you need to decrease the gap which can be done easily by having your mouthpiece converted for Flex Couplers.

The correct gap for each mouthpiece/trumpet system and player cannot be calculated.
It must be discovered through experimentation.

Gap Calculation?

Unfortunately, it is not possible to calculate the correct gap for a system or individual. Remember that adjusting the gap is primarily an acoustic phenomenon. It affects the relative intonation of the notes (pitch center).

Because each player pushes their lips into the mouthpiece by a different amount, this alone affects the relative intonation of the mouthpiece/trumpet system. The video to the right shows this in graphical terms.

The video below explains why gap calculations don’t work.

Annulus (gap) Frequently Asked Questions