Science: Phon

In a clangorous world in which municipal antinoise campaigns have attracted wide and favorable attention, most laymen know that a decibel has something to do with the measurement of din, although few could define the term. Meanwhile acousticians have taken up a newer and less well-known unit, the phon, which may well become familiar to laymen because it is even more closely related to the sensibilities of the human ear than the decibel.

The decibel is an arbitrary unit such that, starting from the zero level or threshold of hearing, each increase of one...