A scale developed originally by K.D. Kryter in 1959 to attempt to measure the perceived noisiness of jet aircraft by observers on the ground. The scale has been adopted by the International Standards ...

An hourly average of the noise level (HNL) including number of flights per hour N is also used and defined ... Correlation to community reaction is shown in the following chart for the CNEL scale ...

Contours of decibel levels of the sound emitted from a supersonic jet. The nozzle exit is located at the magenta dot in each figure, and the jet flows from the nozzle to the right.

The decibel, often written ... Below is a chart from Tinnitus UK that shows common everyday sounds and the corresponding dB ...