Children often hear very high frequencies that many older adults can no longer detect.

The longer version

The high end of the sensing membrane takes the most wear, because that region sits where incoming waves concentrate their energy first. Years of ordinary exposure, illness and reduced blood supply thin out hair cells there, so the ceiling drops steadily and quietly. Loss of that region also makes speech in noisy rooms harder to follow, since the cues there carry most of the consonants.

The change is called presbycusis, and it usually shows up as trouble with consonants and with high voices rather than as general quietness. Some devices exploit the gap by emitting tones above the adult ceiling that younger ears can still catch.

Where this entry sits

Sound and Music gathers facts about how vibrations move through air and water, how ears turn them into meaning, and how instruments and notation shape what listeners hear. Expect echoes, pitch, volume, acoustics, and the odd silence in between. The full list sits on the Sound and Music page, where every entry is listed in order.