Brass Instrument Force Sensor


This is a live demonstration of the data generated from a prototype electro-mechanical device I designed and built for capturing biometrics, specifically the mouthpiece force, of playing a brass instrument. See the Demo section below for an explanation of the video.


Among the many physical aspects of playing a brass instrument, the force of the mouthpiece on a player's lips, colloquially referred to among musicians as “pressure,” garners significant attention from music professionals and educators, not only for pedagogical reasons, but also because using large amounts of force raises the risk of injury. Changing the force of the mouthpiece on the lips changes the tension in the player's lips as they vibrate, greatly affecting the quality and pitch of the produced sound. Even very small changes in the force while holding a single note varies slightly the pitch and timbre, somewhat similar to a guitarist adjusting the tension in a guitar string, but also significant increases in force aid in the ability to produce notes in the upper register of the instrument. However, using too much force while playing a particular note can decrease sound quality, push the pitch sharp, inhibit sound production, or cause injury. The musician negotiates this balance constantly while playing, and mastery of this is extremely difficult.

Given that too much force is generally considered negative, one popular approach to this issue is the idea of playing with “no pressure.” However, it has been shown that there is a minimum amount of force required to keep an airtight seal between the mouthpiece and the lips, typically increasing in proportion to increased pitch and internal air pressure, and this approach ignores that an increase in force is useful for many players to produce notes in the upper register. Another approach suggests that limited attention should be paid to force based on the observation that many world-class players play in the upper register with high amounts of force. But this approach ignores the boundaries that do exist (losing the seal between the lips and mouth piece with too little force => stopping the lips vibrating with too much) and the usefulness of understanding how the force within those boundaries relates to optimal performance and long term health.


I hypothesize that in holding other variables constant (e.g. air pressure, embouchure, loudness), ideal force values can be measured that produce accurate pitch and quality tone for any given note and that these ideal values will vary from player to player. A custom force transducer is required, and in 2010 I designed and constructed a prototype consumer device that measures the mouthpiece force. The idea of measuring this force is not new but there is no consumer product on the market to my knowledge. In practice brass players could use the sensor as a visual reference tool, similar to how musicians currently use a pitch tuner, for monitoring tendencies to use too much or too little force when changing registers or when fatigue sets in, for example. Additionally, software could “learn” optimal force values for an individual musician and record releveant data over time, allowing comparison of playing data over a period of days or even years. More nuanced information could be gathered from measuring this force as well such as the relationship between slurring and tonguing a note in the upper register. At the very least it is useful to rule out mouthpiece force as a potential cause of a playing a problem or know when a player may be using excessive force that could cause injury.


A video demonstrating the device in use is shown above. The measured force for the real-time, sounded note is the rightmost value on the rolling graph. The first thirty seconds demonstrate the transducer sensitivity in playing a passage. The remainder of the video demonstrates how the sensor could help strive for consistent force values when tonguing or slurring to a note in the upper register.

Peak 1:

The force used to slur to a high F under normal playing conditions.

Peak 2:

The force used to tongue the high F under normal playing conditions (~ 30% more force)

Peaks 3, 4, 5:

Sincere, but failed, attempts to tongue the F with the same force as the slurred note while maintaining accurate pitch and quality tone

Peak 6:

The F successfully tongued at the same force as the slurred F (Notice an increase in sound quality)

Peak 7:

The force used to slur to a high F again

Assuming that Peak 1 and 7 represent the ideal force value, I could use the sensor as a visual aid to learn to tongued a high F with force similar to the slurred high F, presumably reducing the chances of too much force hindering accurate pitch and quality tone.

Current State and Conclusion

Ideally, measurements of all elements of playing a brass instrument (internal air pressure, air velocity, force, loudness, etc.) would provide a model for understanding the science brass playing. There is much about playing brass instruments that even the best players and educators don't understand, or much of what they do understand often is not applicable to students with different dental structures or body geometries. Unfortunately, my limited funds didn’t allow me to finalize the sensor design and produce it as a consumer product. I believe it is a worthwhile venture, though, and perhaps it could be finished in the future. In the meantime, I plan to continue researching how it could be a useful tool with my private students. Please contact me with any feedback you may have.