A unit of perceived noisiness equal to the perceived noisiness of random noise occupying the frequency band 910-1090 hertz at a sound pressure level of 40 decibels above 0.0002 microbar; a sound that is n times as noisy as this sound has a perceived noisiness of n noys, under the assumption that the perceived noisiness of a sound increases with physical intensity at the same rate as the loudness.