I read recently that “…a rather disturbing fact [is] that our hearing deteriorates with age” and that “this is especially significant at the higher frequencies.” The article went on to say that “…by the sixties most people have difficulty in hearing sound above 12 KHz”; and that “25% of a population may have a threshold over 15 dB above the minimum (hearing loss of 15 dB) and 10% over 25 dB above.” – Read more