I lose 120 FPS with this installed and 0 props on the map

Here are the 16 laggiest hooks found during the last 929 frames:
Impact Executions Mean t /f Max time
33.20% 928 1357.772us 22033.6us
Event "Think", hook "FlyBySound_Think"
in "lua/autorun/sh_flybysounds.lua" (lines 44 to 119),
found in Workshop addon « Fly By Sounds (FIXED) »

Please dev optimize this mod
As an easy band-aid fix you could only have the effect apply to props that are not sleeping instead of using Think.