The metric for Perceived Noisiness turned out to be far less robust than the metric for Loudness. It was an early indication that the acceptability of a sound was product specific to a certain degree.
The unit noy was introduced by the American acoustics engineer K. D. Kryter in 1959.
A jet aircraft on takeoff is around 110 noys.
An observer uses the unit to described the noise levels he or she experiences as multiples of a standard level. The standard level, one noy, is defined to be the noisiness of a random noise signal within the frequency band from 910 to 1090 hertz at a sound pressure level of 40 decibels.
See also: Loudness.
Subjects: Noise & Vibration