Presbycusis raises the audible high-frequency floor with age, so tones vanish for adults

Evidence

The original teen buzz was created by recording the output from a mosquito device, but nowadays there are plenty of synthesized downloadable teen buzz ringtones available on-line. In general, these ring tones are not audible to adults over 25 years of age, but this does depend on the overall amplitude of the sound and the rate of presbycusis change for given individuals. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2570

Categorization

• CANDY: Teenagers weaponized the anti-teen device into a ringtone adults literally cannot hear — instant elevator material.
• DEFINE: Presbycusis (age-related hearing decline at high frequencies) is the mechanism, though the book mentions it only in passing.
• XREF: Ties to the chapter’s earlier treatments of equal-loudness contours and age-related threshold shifts.