F35 Southbound Takeoff Noise Chamberlain School

This was recorded in the Chamberlain School parking lot. The jets were taking off to the south this time.

As I did last time, the first group of jets were measured with C-weighting (includes low frequencies), the next group of four were measured A-weighted (industry standard, removes low frequencies from measurement), but the last jet I went back to C-weighting, giving a higher reading.

The volume levels are lower than the northbound takeoff. To the north, the planes are much closer to the school during liftoff and the first portion of their flight path. They are visible from the parking lot soon after liftoff. The southbound takeoff puts them substantially further away from the school, and are even further away once they gain enough altitude for their exhaust to be heard at its loudest. (See embedded map crop) As such, the southbound graph blends them all together into a lower-volume generalized roar; the northbound graph showed the noise from each jet more distinctly.

The 'headline number' for the southbound takeoff is 'only' 99.2 dB-C for the final jet. Versus the 109.7 dB-C for the northbound takeoff. Of course these values will vary somewhat depending on exact flight paths immediately after takeoff and wind direction and speed. But unlike I expected, the northbound takeoffs are louder at the school, mostly due to their being closer to the school during and after takeoff.

Click the graph to enlarge it full-screen.