So basically I want to sync the beat with the size of the blur effect(Making sure it's obvious with the beat)
beat = game.Workspace.Sound.PlaybackLoudness while true do game.Lighting.Blur.Size = beat wait(.1) end
I am pretty sure that script is correct, make it is a local script and u put it in StarterGui, or StarterPack, or StarterPlayerScript
The problem is that you're referencing what the PlaybackLoudness was when the script first ran. You should instead update it each time it is needed again (when the blur is set).
local beat while true do beat = game.Workspace.Sound.PlaybackLoudness game.Lighting.Blur.Size = beat wait(.1) end