Editor,

Terry Sparks’s claims about Growler noise levels are a mixture of pseudo-science and wishful thinking.

True, “Most people do not use the decibel unit of measure.” Sadly, neither does Mr. Sparks. As an audio engineer, I do understand decibels. This is wrong: “… decibel level decreases by the square of the distance in the air. Thus, a 150-decibel jet engine noise level will drop to 81.6 decibels a half-mile away and down to only 75.5 decibels a mile away.”

Decibels are logarithmic and decrease linearly as a function of distance. Mr. Sparks’s example of 75.5 dB versus 150 dB corresponds to a distance approximately 5280x farther away from the sound source compared to the original measurement position. A 150 dB(A) point source measured at 50’ is down to 75.5 dB(A) at a distance of 50 miles! At 1 mile from a source measured at 50 ft, SPL is 109.5 dB, still really loud! To be fair, these calculations depend on the original mic position, which I’ve taken to be 50 ft (FAA webpages). For the SPL to be 75.5 dB(A) at 1 mile, the microphone would have been only 12 inches from the jet engine, nonsensical.

Mr. Sparks’s also seems to claim to be a marine biologist. Someone with expertise in that area might comment. My opinions about Growler noise. Growlers are incredibly loud, and their noise can be heard at very high levels throughout this geographic region: San Juan Islands, Port Townsend, La Conner, etc. So, we are not “just a couple hundred” people.

Second, we’ve lived here for 34 years, and we took some amount of noise and flight operations as part of the deal, but Growlers are much louder and the number of flight operations has quadrupled So, don’t tell us that we knew what we were buying into.

Third, Growlers don’t have to be stationed here. There are other less impactful locations available.

Fourth, the Navy lied about Growler noise and misled the public.

Paul Mathews

Langley