When I use the term “breath support,” students and colleagues often echo back something like “oh, right, more air.” But is breath support the same thing as “more air?”
Measuring quantities of air isn’t completely straightforward—when we say “more air,” we might rightfully wonder whether that means a greater volume filled with air, or a greater number of air molecules, or whether we’re really thinking of something like airflow or air velocity.
For my purposes in teaching, I find a few different measures to be relevant:
First, you must set up breath support with a good inhalation, and I think it’s generally helpful to inhale a large volume of air into the lungs.
Then, you must pressurize the air by engaging the torso muscles, constricting the space in which the air is contained. (The diaphragm’s relaxation alone does create pressure, but not enough for good woodwind playing.)
The increased pressure makes the air escape your embouchure at a higher velocity. You can adjust the size of your embouchure, allowing more or less air to pass through, which is the basic mechanism woodwind players use to change (sound) volume (or “dynamics”).
I’m most directly concerned with air pressure when I talk about breath support, and in some ways in which that does translate to “more” air. But since “more” can be measured in multiple ways, I like to use a more exact term like “breath support.” That also has the concreteness of referring to something that the player actively does, rather than focusing the imagery on air, which is invisible.
Be precise in your pedagogical vocabulary, and consistent in your breath support.