Why does my script detect a sound, get it's playback loudness, and just doesn't see it properly?

hi! my script is supposed to be a visualiser but it just sits there, with no size. anyone know why?

print("loading")
local counter = 0
script.Parent.Sound:Play()
print("played sound")
while true do
if counter == 200 and script.Parent.Sound.PlaybackLoudness == 0 then
error("Timeout due to sound error")
end
wait()
print(script.Parent.Sound.PlaybackLoudness)
script.Parent.Size = Vector3.new(5,script.Parent.Sound.PlaybackLoudness,5)
counter = counter + 1
print("Millisecond "..counter.." has been registered")
end
print("loaded")

this is a server script edit: the error happens with local scripts too