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Making a Case for the Lowly 7C (and 12C for Trombone!)


There has been a trend with some directors for several years to disregard the 7C/12C mouthpieces for students. Some believe that these sizes are for beginners only, and some even don’t even want them for beginners, instead opting for a larger diameter mouthpiece. I want to make the case for why your students should stick to the tried and true 7C/12C offerings. But first, let’s make sure we are on the same page with understanding the mouthpiece nomenclature. This information applies both to Bach trumpet and trombone mouthpieces.




The Number refers to the diameter of the inner rim. The lower the number, the wider the inner diameter. Inner diameter has two primary considerations: embouchure fit, and tonal goals. Let’s break that down.

Embouchure Fit - much like shoe size, to some degree the player must pick a mouthpiece diameter that will fit their embouchure. However, it’s important to know that players of all lip sizes and thicknesses have historically played with much success on both small and wide diameter rims. If a player has fuller lips, they will need to accommodate any mouthpiece diameter by some amount of rolling in.

Tonal Goals - in general, a wider diameter will enhance the lower overtones due to the increased vibrating mass underneath the mouthpiece rim. Think of a guitar. One can play a 4th space “E” on 6 different places on the guitar fretboard. On the thinnest E-string the sound is the brightest. At the 5th fret on the B string, which is a slightly thicker string, the sound is a bit darker. Once you are at the 24th fret of the largest E string, the tone is dark and dull.

The Letter refers to the cup depth, “A” being the deepest, and “F” being the shallowest. A deeper cup has few upper harmonics, thus resulting in a darker sound. A shallower cup emphasizes the upper harmonics, thus resulting in a brighter sound.

FWIW - Schilke & Yamaha are opposite of Bach: the larger the number, the larger the i.d. The A cup is the shallowest, and the E is the deepest. 

The two factors - inner diameter and cup depth work together to determine overall cup volume. Large volume cups require more energy and are less efficient.




Now that the treatise on brass mouthpiece basics is out of the way, let’s focus on why the 7C is a good choice for nearly all of your students (including your beginners).

The 7 rim is not a small diameter. For all intents and purposes, Bach makes trumpet rims with inner diameters (i.d.) ranging from 15mm-17mm. During the 60’s and before, the Bach 10.5C was what most students started on and what most professionals played (with an i.d. of 15.9mm). The 7C has an i.d. of 16.2mm - slightly larger than the median. So by starting on a 7C, we are already on the larger side of the i.d. spectrum.

Why does this matter? For developing players, a medium inner diameter (i.d.) helps with two things that are crucial for school-aged players:

  1. It allows for the characteristic trumpet sound. One that has clear fundamental, but with the shimmer of upper harmonics.
  2. Most importantly, a smaller i.d. supports embouchure development. A large i.d. for players that are not properly developed will cause them to pinch their lips together and press the mouthpiece hard into their lips - both of which are recipes for poor range, endurance, and tone. This habit for most players becomes a life-long struggle with the instrument.

Some of the world’s greatest players started and played their careers on mouthpieces with a smaller i.d. (Bobby Shew & Allen Vizzuti plays a mouthpiece that is like a Bach 10.5, and the venerable Bud Herseth played a Bach 7B in his early years at the Chicago Symphony, until scar tissue from a car accident forced him to move to a larger i.d. mouthpiece).

So why should a school-aged brass player play a mouthpiece larger than a 7C? 

The only consideration should be if they are requiring a sound that has fewer overtones and is thus overall darker than what they can achieve on the 7C. But only if they have good range (can easily play up to high C) and have plenty of endurance. If these two qualifications aren’t met, I would not recommend moving up in size.

But won’t they just learn to grow into the bigger mouthpiece, and then have even stronger chops in the long run? Hah! Absolutely not! It’s more likely that they will develop the dreaded 3 P’s of poor brass playing - Pinch, Press, and Pray! Unless they have properly developed the muscles of the embouchure, and have learned the proper mechanics of how to play their embouchure, a larger inner diameter mouthpiece will only encourage these bad habits.

I hope after reading this you will see that the 7C/12C mouthpiece should not be dismissed. Many professional musicians make their living playing mouthpieces this size (really, it’s only the professional Symphony Orchestra players who consistently select the larger i.d. as the tone of the trumpet in modern orchestras has changed over the last few decades to become less brilliant). It’s also a good choice for your students.


Have thoughts? Drop me a line!


Donovan Bankhead


Ernie Williamson Music