Translation of "wrong note" into Italian

And if he hits a wrong note, the brain immediately lets him know about it!

E se prende una stecca, immediatamente il cervello glielo fa notare.

But a lost case is still a wrong note.

Ma un caso perso resta una nota stonata.

But as Beethoven said, a few wrong notes may be forgiven, but singing without feeling cannot.

Ma, come disse Beethoven, qualche stonatura puo'essere dimenticata, ma il cantare senza sentimento, no.