Playing wind instruments louder shifts spectral energy toward higher harmonics.

Evidence

Universally, when wind instruments (including the voice) are driven harder, the strength of the higher harmonics grow relative to the lower harmonics. The sound becomes more brilliant, or perhaps develops too many high harmonics and begins to sound raspy, according to the effects of autodissonance and overlap of harmonics on the basilar membrane. The vocal folds, for example, suffer more violent and abrupt opening and closings when driven at higher pressures, which necessarily generates stronger high harmonics. — Eric J. Heller, Why You Hear What You Hear- An…, 2257

Categorization

• XREF: Explains why loud brass and voice sound ‘brighter’ — connects to perceptual changes tied to intensity discussed throughout the hearing literature.