A unit of noisiness, perceived noise level, or perceived loudness. It is calculated from the sound pressure level in phons of a reference sound subjectively judged to be as noisy as the sound being measured. The reference sound is spread over 1 octave, centered at 1000 Hz.
where N' is the perceived noise level in noy and N'' is the sound pressure level in phons.
| home | | | units index | | | search | | | to contact Sizes  |
| | acknowledgements | | | help | | |
Copyright � 2003 Sizes, Inc. All rights reserved.
Last revised: 4 May 2003.