How much mouthpiece pressure is necessary? How much is ideal?
The short answer is, “as little as you can get away with.” The longer answer is more complex.
Mouthpiece pressure affects endurance, range, flexibility, and tone quality in various ways. Too much pressure can not only hurt your endurance, but can actually damage your lip muscles — in extreme cases, permanently.
First, let’s talk about the role of the mouthpiece.
The Role of the Mouthpiece
The pitch of any vibration is determined by the length of the vibration and the tension of the vibrating body (string or membrane). A violin string is stretched at a fixed tension between the bridge (on the body) and the nut (near the pegs). To change the pitch, the violinist uses their finger to change the length of the string… shorter is higher. The pitch of a drum is determined by the diameter of the rim and the tension at which it is stretched. By contrast with a violin, the length (diameter) of the vibration of a timpani is fixed; the player changes the pitch by using the foot pedal to change the tension on the drum head… higher tension makes a faster vibration and therefore a higher pitch.
The mouthpiece acts like the rim of a drum, or the bridge and nut of a violin string. The diameter of the mouthpiece determines the maximum length of the vibration. But we have more complex control of the vibration within that perimeter. Using our lip and facial muscles, we can:
- Increase and decrease the overall tension of the membrane (our lips) using the dynamic tension between the lip muscles (which pull the lips together) and the facial muscles (the “sneer” and “smile” muscles) which pull them apart.
- By pressing the lips together (and with the help of the jaw) we vary the size of the aperture, affecting the length of the vibration inside the mouthpiece.
Another way we control pitch is by varying the speed of the air through the lips and the shape of our oral cavity, using our support muscles (abdominal muscles) and tongue. Faster air causes the vibration of the lips to interact with the impedance of the instrument to cause our lips to vibrate in higher harmonics with the standing wavelengths in the instrument, making higher notes.
Mouthpiece Pressure and Flexibility
When we use too much pressure, we trap the lip and facial muscles. They lose the ability to move freely and easily from higher to lower tension, which limits our ability to change pitch, perform lip slurs and trills, and move between higher and lower registers of our instrument.
Mouthpiece Pressure and Tone Quality
Mouthpiece pressure stretches the lips. Thinner membranes make brighter sounds. This is true of drums and violin strings, and it is true of lips.
Perhaps you aspire to be a lead player in a jazz band, who likes a bright sound. But given the downsides of mouthpiece pressure, there are better ways to achieve it, e.g. using a shallower mouthpiece with a tighter backbore, or a lighter weight trumpet. Lead players also need “chops” — range and endurance — and mouthpiece pressure destroys both.
So Why Do We Press?
Ideally, mouthpiece pressure constrains the vibration and counteracts the outgoing pressure of our air stream.
But it can also become a crutch. Pressure also stretches our lips against our teeth, increasing the tension of the vibrating membrane (our lips), which gives us a higher note. We often do this when we are tired — our muscles just can’t create the dynamic tension mentioned above to create the higher note, so we stretch our lips mechanically using arm strength. But here are the problems:
- Our arms are stronger than our lips. They win. Our lips give up and collapse.
- Our mouthpiece pressure cuts off the blood flow to the lips. Blood delivers energy (oxygen and sugars) to our muscles. Without blood, our lips lose energy, and tire faster.
- Our mouthpiece crushes the muscles. They become bruised or, in extreme cases, they tear.
In the larger scheme; when we get in the habit of using pressure, we get out of the habit of strengthening our lips in ways that can give us progressively better endurance, range, flexibility, and tone quality.