# EIS: F-35 has a maximum loudness that is more than 4 times louder than maximum loudness of the F-16

Sound level, sound intensity, and loudness are explained in the Air Force draft Environmental Impact Statement (EIS).

The bottom line is, according to figures in the EIS, the maximum loudness of the F-35 is more than four times louder than the the maximum loudness of the F-16 both at takeoff and landing.

The EIS explains the difference between three concepts: sound level, sound intensity, and perceived loudness

Here are the numbers and explanation, all from the EIS:

Table BR3.2-1 on page BR4-18 of the EIS gives the Lmax for the F-16C and the F-35A

Lmax is the maximum sound level

for takeoff:
Lmax is 94dBA for the F-16 and 115dBA for the F-35, a difference of 21 dBA

for landing:
Lmax is 73dBA for the F-16 and 95dBA for the F-35, a difference of 22 dBA

The second volume of the EIS explains on page C6 that dBA is an adjustment made to the measurement to correspond to the frequency sensitivity of the human ear. Pages C5 and C6 explain how sound level is related to sound intensity and perceived loudness.

On page C-6 of the EIS we read: “A change in sound level of about 10dB is usually perceived by the average person as a doubling (or halving) of the sound’s loudness, and this relation holds true for loud sounds and for quieter sounds.”

The F-35 has a maximum sound level that is 21dBA higher on takeoff and 22dBA higher on landing. Under that rule of thumb provided in the EIS we can consider that the first 10dB of the 21dB is perceived as a doubling of the loudness from the F-16 level. The second 10dB of the 21dB is perceived as a doubling from that doubling, or four times louder than the F-16. OK, there is an additional 1 or 2 dBA difference. So we can say “according to the numbers given in the Air Force EIS, the F-35 has a maximum loudness that is more than 4 times louder than maximum loudness of the F-16.”

For those also interested in sound intensity, the numerical difference between the F-16 and F-35 is much greater.

The formula for the difference in sound level in dB = 10 x log (A1/A2) where A1 and A2 are the sound intensities (also called sound amplitudes and sound pressures).

The difference in maximum sound level is 21 dB on takeoff so

10 log (A1/A2) = 21 dB
log (A1/A2) = 2.1
and A1/A2 is 126
where A1 is the maximum sound intensity of the F-35 and A2 is the maximum sound intensity of the F-16.

That means the maximum sound intensity of the F-35 is 126 times the maximum sound intensity of the F-16.
The human ear perceives that 126 times more intense, or higher pressure, sound as being more than four times louder.

For more on sound, decibels, sound intensity, and loudness go to http://www.animations.physics.unsw.edu.au/jw/dB.htm
at this site you can click on the graphs and hear the different sound levels displayed