Brass players cannot hold off-resonance notes because lips form an interactive nonlinear drive

Evidence

Why does a trumpet tend to slide into natural playing frequencies in its lower registers? The playing frequencies coincide with the resonances of the trumpet. If we “lip” it off resonance, we expect that the instrument will not be as loud, but actually it is difficult to play well off resonance at all. The notes tend to slide toward the natural playing frequencies. This is clear evidence that the lips are an interactive drive and that nonlinear effects are at play. In contrast, a strong, high-impedance earbud driver snugged into the leadpipe of a trumpet has no difficulty driving the trumpet at any chosen frequency (see the experiment in box 16.1). — Eric J. Heller, Why You Hear What You Hear- An…, 1544

Categorization

• XREF: The earbud-in-leadpipe contrast mirrors earlier book discussions of high-impedance sources; the claim that limpness of a nonlinear source forces natural frequencies is a general oscillator principle. — connects to: The player’s lips form a variable double reed making brass a stopped-pipe acoustics — David Howard, Jamie Angus, coustics and Psychoacoustics, 1262