What is a positive connotation for screeched?

Answer 1

I am not entirely sure as to whether you mean a positive synonym for "screeched", or whether the word itself has any positive connotations.

A positive connotation for the word "screeched" could be the fact that although it is a harsh and displeasing noise, it is often used in conjunction with excitement.

For example: "Wow!" she screeched, suggests that she is pleased, or incredibly surprised, and therefor is shrieking to express the above emotions.

A synonym for "screeched" I rather like is "caterwauled".

Answer 2

Screech tends to have not only a negative connotation, but also a cacophonous sound. If you yourself are writing, I suggest trying to use a synonym like squeal and yelp.