Loudly driven brass columns self-organize into phase-locked shock waves.

Evidence

In a complete brass instrument, it is possible through the use of an appropriately shaped bell, mouthpiece and mouthpipe to construct an instrument whose modes are frequency shifted from the odd-only modes of a stopped cylindrical pipe to being very close to a complete harmonic series. In practice, the result is a harmonic series in which all modes are within a few percent of being integer multiples of a common lower-frequency value except for the first mode itself, which is well below that lower-frequency value common to the higher modes, and therefore it is not harmonically related to them. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1250 (#complicates, via linked claim)

Categorization

• XREF: connects to: Adjacent in-phase sources boost each piston’s efficiency N-fold through mutual pressure; Brass instrument design transforms odd-only pipe modes into a near-complete harmonic series — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1250

Broader Connections

• Brass instrument design transforms odd-only pipe modes into a near-complete harmonic series #complicates (0.72) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1250