555 is a square wave generator so I don't understand what you mean by "sound is not good", you are not listening to a sinusoidal if this is what you expect.
I made this circuit but sound or voice not exactly when i made in practice
in Proteus program the voice is quick and don't clear but in practice is good
Is there method for modify the voice in Proteus program till it is good?
please any body help me
and thank you for everybody