Audio: High-frequency noise suppression is insufficient at a distance from the aircraft, making it too piercing.

High-frequency noise above 1 kHz primarily stems from the screeching of turbofan engines. This type of noise has very poor penetration; in particular, the barrier created by the air and the glass of the control tower over long distances significantly attenuates the high-frequency components. Meanwhile, low-frequency noise is amplified by building resonance, sometimes even causing a thumping sensation. However, the current EQ does not account for this behavior, so even at a distance,the noise of aircraft taking off in the game still sounds grating.
The recommended EQ adjustment is to gradually apply some gain (+3 dB) to frequencies below 100 Hz as distance increases, while progressively attenuating noise above 1 kHz. It may even be worth considering cutting off ultra-high frequencies above 15 kHz entirely. Compared to real-world attenuation, the in-game suppression of high frequencies can be more aggressive to prevent auditory fatigue and irritation caused by high-frequency sounds.
The following results are provided for reference (these recommendations focus solely on EQ; if you wish to simulate an indoor environment, you’ll need to add reverb as well).