How do I make a sound position into a scaled GUI number?

I am trying to make a sound position thing, and I am having trouble with the sound position. I have tried doing UDim2.new(0.pos,0,0,10), but that doesnt work.

Here is my code:

print(script.Parent.Sound.TimeLength)
local b = script.Parent.Sound.TimeLength*420
local pos = 0
while wait() do
    print(script.Parent.Sound.TimePosition)
    pos = script.Parent.Sound.TimePosition
    script.Parent.Size = UDim2.new(pos/10,0,0,10)
end

Thanks!