Brass Instrument Playing: Scientific Terminology and Physical Feelings

Comments, criticism, and suggestions can be sent to me (Jay Kosta) at - JKosta@pronetisp.net

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There is often confusion and misunderstanding among people (players, students, teachers, etc.) about the ‘mechanical aspects’ of producing sound on brass instruments. A typical situation is that someone uses scientific or engineering terminology as part of the discussion, and another person is thinking it terms of how it ‘feels’. There is value in both approaches because different people achieve understanding in different ways. It is helpful to have both approaches available, in order to have the most worthwhile discussion.

SCIENTIFIC TERMINOLOGY

· Breathing Concerns

DIAPHRAGM Usage – Here is a brief description of the diaphragm obtained by a ‘google search’

“The diaphragm is a C-shaped structure of muscle and fibrous tissue that separates the thoracic cavity from the abdomen. The dome curves upwards. The superior surface of the dome forms the floor of the thoracic cavity, and the inferior surface the roof of the abdominal cavity. The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges. The reality is that we don't have sensory nerves in our diaphragm, so we don't feel its action like we might another muscle, but we can consciously choose to use it or not.”

The diaphragm usually functions without conscious thought – when we inhale it contracts to allow the lungs to expand, when we exhale (or blow out) it relaxes and allows the lungs to reduce in volume. The diaphragm CAN be consciously controlled. It can be contracted by expanding your abdomen, by making your belly and lower back expand; similarly, the diaphragm can be allowed to relax by stopping that muscle effort.

Lung Expansion – When the lungs expand, its tissue is stretched, as is other tissue (and muscles) in your torso. On exhale the tissue goes back to it original size. The reduction in size causes the air pressure in the lungs to rise, and that results in air flow out your mouth / nose. In addition to relaxing the ‘muscles of inhale’, you can also tighten other torso muscles to produce additional force on the lungs which can increase the exhale air flow.

AIR PRESSURE in your lungs, throat, and mouth

The air pressure is normally the same in all those locations – because they are all connected by ‘open large capacity tubing’ which immediately causes any slight change of air pressure in one area to be conveyed throughout the entire system. If extreme constriction (which is not normal or advised) of the ‘tubing’ is done, then air flow is severely restricted.

When playing, the only restriction to air flow should be controlled use of the lip aperture. The lip aperture is controlled by the muscles surrounding the lips and mouth.

· Tongue Usage

The tongue is often used by players to assist in adjusting the lip aperture, and teeth & jaw position. The muscles used to move the tongue have an effect on the tissue and muscles that affects the entire embouchure. And to be clear, I don't think it is the actual 'physical position' of the tongue that alters lip adjustment. It is the muscle tension that is used in the process of attempting to move the tongue, and the effect that the muscle tension has on the lips and jaw is what is meaningful.

… try this… make your usual lip aperture and gently place your fingertips on upper and lower lip. Then blow and also FORCEFULLY move your tongue to the AW and EEE positions – you will feel a change in your lips and your throat below your jaw. Next, try to keep your tongue low and unmovable, and exert the same tongue muscle effort – your tongue will move only slightly, but you will feel a change on your lips and throat.

The movement and position of the tongue doesn’t affect the air pressure. When attempting to ‘blow harder’ or ‘faster’ some people do forcefully move their tongue as part of the effort . Also, some people have good results by consciously moving their tongue to achieve lip adjustments as they also control how hard they blow.

· Bernoulli’s Principle

Bernoulli’s Principle is often mentioned in discussions about lip aperture function, but it is unclear if knowledge of it can be useful for brass playing. See here - https://wilktone.com/?p=2159 for various thoughts about it.

My guess regarding its affect on lip aperture is that the slight decrease of air pressure on the ‘pathway walls’ through the lips might assist in the periodic closing of the aperture which produces the air pressure oscillations – the sound.

I envision the sequence of aperture oscillations as this – lips are closed, internal air pressure opens the aperture and allows air flow, Bernoulli’s Principle causes a slight reduction of air pressure against the walls of the aperture, that reduced pressure and the ‘resonance pressure’ inside the mouthpiece cup causes the aperture to close, the air pressure in the mouth again opens the aperture, and the cycle continues.

PHYSICAL FEELINGS

· Breathing Concerns

Air flow can be increased by ‘blowing harder’ and by ‘blowing faster’ – they both happen because you’re creating more internal air pressure and forcing the air flow through your lip aperture. The ‘force’ needed to enable you to blow harder comes from your tightening various muscles in your torso to ‘squeeze’ the lungs. In most playing situations, the muscles that are used to ‘squeeze’ are in the upper chest and upper back, with the muscles in lower torso used to a lesser extent. If you hold your breath and squeeze your lungs, that causes the air in the lungs to be ‘compressed’ which increases the air pressure.

Definitions

These are beginning thoughts about - flow, pressure, compression, volume, resistance, etc.

Air Flow and Flow Rate – air in motion (flowing) is felt as wind. And since there is motion, there is a rate at which it is moving. The rate is usually expressed as the volume of air moving per second across a location – a related example is a river flow of 1000 cubic feet per second between its shores.

Air Speed – this gets complicated, but for purposes of playing a brass instrument, once the desired pitch is produced, the lung air pressure determines the flow and air speed through the lip aperture.

With an established aperture setting, the exhalation effort controls the lung air pressure.

For ‘deep science’ about gas motion, I found this website - https://courses.lumenlearning.com/boundless-chemistry/chapter/kinetic-molecular-theory/

Loudness or dynamics – once the embouchure is set for a particular pitch. The lung air pressure will control the dynamics, that is, loudness of tone. The player can directly control air pressure of tone by varying the exhalation action.

Release of Air – when playing there are two primary control mechanisms: use of the torso muscles to adjust the pressure of the internal air, and control of the lip aperture size.

Lung Air Capacity and Outward Air Flow – capacity is the maximum quantity of air (usually measured in liters) that can be exhaled after doing a maximum inhale. This could also be called the maximum volume of air that can be exhaled. As the lungs get filled during inhale, the internal volume increases and the tissue gets stretched and is in tension. When the muscle effort of performing the inhale is stopped, the tension causes the lungs to attempt to deflate (reduce the internal volume). When the internal volume is decreased, the air inside the lungs is slightly compressed which causes the internal air pressure to be greater than the external environment air pressure, and that difference in pressure results in air flowing out of the lungs and through the mouth & nose. We are able to control the outward air flow by use of torso muscles, and by controlling the size of the mouth/nose opening.