3 Inherent Problems with Gap Formulas and Studies

A lot of great, in depth work has been done about the trumpet mouthpiece gap. Unfortunately, many of the frequently cited formulas and studies on the gap have inherent problems that create erroneous results, which when relied on, will deter trumpet players from achieving optimum results with their equipment. I’ll address three of these inherent problems here.

Problem #1 – Failure to Take The Player Into Consideration

As we have written about previously, a proper study on the gap must include all three essential elements of the system – the trumpet, the mouthpiece, and the player. Having helped thousands of players through the years to fine tune their gap, we have no doubt that the player is the most important variable of the Player-Trumpet-Mouthpiece System.

No gap formula or theory to date has been able to calculate what a player feels, and most importantly, what a player prefers to feel. Yes, there are certain generalizations about the gap and ranges of sizes that many players fall into.

Relying on these generalizations is as silly as blindly buying a men’s size 9 or 10 shoe because that’s the range of shoe sizes most commonly sold, even though you are a woman who wears a woman’s size 8.

Relating this back to the gap:

Find the gap that plays the best for you, not what someone else told you should feel the best for you.

Problem #2 – Failure to Take Changes in the Equipment Into Consideration

We know that a change in the gap changes the acoustical impedance in the Player-
Trumpet-Mouthpiece System. It is also well settled that there are thousands of other variables in the mouthpiece and trumpet that can change the acoustical impedance in the System.

Due to the nature and limitations of mouthpiece and instrument manufacturing, it is impossible to consider every variable that affects acoustical impedance. Put another way, it is impossible to isolate and therefore calculate, what the gap should be considering every variable.

The gap formulas and theories sometimes attempt, but do not succeed in addressing every variable in the equipment and therefore cannot predict anything with any consistency.

Problem #3 – Failure to Take The Environment Into Consideration

While the first two problems on this list are the most important inherent problems in any gap formula or theory, the third problem — considering the environment — is worthy of a mention.

For argument’s sake, let’s say that we can calculate an optimal gap considering the player, the mouthpiece, and the trumpet. We know that the acoustical properties of the environment you are playing in can affect the acoustic impedance you feel as a performer.

Playing outside in hot, humid weather and then moving inside a air-conditioned, dry, acoustically “stuffy” room can drastically change the acoustical impedance, and in turn, what you feel.

In today’s musical climate, you could easily find yourself in a stuffy recording study, then in a huge, open cathedral. While most players would not think to adjust the gap in these situations, a significant minority of players have fine-tuned the gap to their varying situations.

Learn More About the Gap

History of the Mouthpiece Gap & Bob Reeves Sleeve System: Part I

Carroll Purviance, Mouthpiece Maker
Mouthpiece maker Carroll Purviance.

The Early Years

The first time I learned about the gap was on a visit to Elden Benge’s Burbank shop. He explained to me how he made his trumpet play better in combination with Bach mouthpieces, which were popular at the time. He moved the receiver on the horn back until it played the way he liked it. Benge’s goal was to find the gap that worked best, not find out what the gap was “supposed to be.”

When I went to work for Carroll Purviance in 1961 he had two shank sizes for his mouthpieces, his standard, and a smaller B shank. Purviance discovered that for some setups, one shank would play better than the other.

During that same period I was studying trumpet with John Clyman, who had his own theories about the gap. He believed that there should be at least some gap between the mouthpiece and leadpipe. This was contrary to another theory that suggested that very little, or no gap was best. Clyman would push me to work on mouthpiece projects for him in exchange for the lessons he gave me. He then bought my first lathe (which I still use today) and I opened  up my own shop in the back of my Mother’s house.

Opening Up Shop

In April of 1968 I opened my shop in Hollywood, California and was fortunate to attract the top brass players in the world. My shop was a sandbox where we would try all the ideas we had on our minds. Some turned out good, some bad, but it was fun and a unique learning experience.

Bob Reeves Trumpet Mouthpiece with Sleeves
A Bob Reeves trumpet mouthpiece cut for sleeves with sleeves.

My experiences with Benge, Purviance, and Clyman, along with my day-to-day observations of players made me realize how crucial the gap really is.  Discovering the proper gap was a time consuming process, requiring a lot of salvage work on customers’ mouthpieces. I would think that the gap should be increased so I soldered a new shank on the mouthpiece, only to find out that it should be smaller and had to file down the shank, or vice-versa.

The Bob Reeves Sleeve System

It only took a few times of going through this painstaking process to figure out that there must be a better way. This planted the seed that grew into my adjustable sleeve system. Thanks to my friends Bill Cardwell and Don Macintosh,  in 1974 I was granted my first patent for the sleeve system.

Check back for Part II of this series!

Click here to learn more about the Bob Reeves Sleeves System.