The harder the vibrating plane, the lower the actual distortion. Putting a light finger on a nylon string (or a classic speaker membrane) makes a huge differen

The harder the vibrating plane, the lower the actual distortion. Putting a light finger on a nylon string (or a classic speaker membrane) makes a huge difference, a thick steel contrabass string doesn't really change its frequency until you quite forcefully push it into the fingerboard. I expect you'd have to push hard into the vibrating gorilla glass of a smartphone screen to influence the sound audibly.