This is a short post because the link is a very long one, provided by one of the family. It relates to the physiological and neurological effects of sound at excessive levels.
The implications are interesting given the way both technology and use have developed over the last three or four decades. It might explain a lot.
As it happens three years ago I put up a post of ordinary length dealing with the same overall subject at a more basic level.
The reason for the omnisonic link is because a lot of my life was spent in dealing with the effects of deafness in various ways amongst numbers of other people.
Also, that I am old enough to recall the catastrophic effects on the hearing and health of many people before serious measures were taken to control levels of sound in workplaces.
Now it is not the old but the young who seem to be at the most risk.