Can anyone help me with this chunk of text?
Context: They're talking about a squeaky noise that recorders make when you twist them
For the first line I have "This sound is what makes the recorder seem fun"
I'm having trouble with the よいとされている part of the second line... Does that mean something along the lines of "necessary to be good"?
And I have no idea what the 通でない part of the third line means...
Can anyone shed some light on this for me?