High-frequency deterrents work amid ambient music because music lacks energy up there

Evidence

These units have proved themselves to be successful deterrents, saving considerable police time and effort in moving on gatherings of young people, and they are now used quite widely in public spaces. The unit will work in the presence of other sounds such as music, which typically contains no high-level energy at these high frequencies. Young people report these high-level high-frequency sounds to be very annoying, unpleasant and irritating. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2575

Categorization

• XREF: Connects to a broader theme of acoustic weaponry and targeted sonic exclusion used in everyday urban life.
• SEED: An angle: how the same presbycusis-driven tech became both an anti-youth harassment device and a youth-only communication channel — the double edge of acoustic targeting.

Related

• An 16.8 kHz sine wave is used commercially as a teen deterrent (similarity 0.79)