Issue with an rbx soundeffect script

Question

In this script of rbx soundeffects

sound.Volume = FootstepsSoundGroup:WaitForChild(humanoid.FloorMaterial).Volume * (vel.Magnitude/12) * humanoid.Loudness.Value
        sound.EmitterSize = FootstepsSoundGroup:WaitForChild(humanoid.FloorMaterial).Volume * (vel.Magnitude/12) * 50 * humanoid.Loudness.Value

Output shows:

Loudness is not a vaild memeber of "Workspace.mudavoor.Humanoid"

What changes i want to do in this script? to get sounds