Sine VS Square wave efficancy?

[eCue]

This video demonstrates that square wave starts out rough/ noisy and smooths out as frequency is increased.

That's due to the (probably unintentional) filtering provided by the signal generator and test setup.

I was thinking his equipment might not be able to capture the higher frequencies and if it it did we could not hear them but would need graphs to see the behavior. He stopped looking at the higher frequencies when likely the square wave is still giving a higher amplitude

This video answers some questions

[youtube]7pECYtzX1fY[/youtube]