Random Values Gained From Sound Sensor
Here's the circuit from your "sound sensor:"



Source.

Your so-called  "blue relay" is a potentiometer.  You use the potentiometer to set the sound level at which the D0 output changes state.

A0 will be greatly influenced by the setting of the potentiometer.  

Your code is reading the audio level once per second.  Audio changes thousands of times per second.  

Whatever you are reading from the sound sensor is in no way a good represenation of the sound in the room.  It'll be more related to the potentiometer setting than to the audio.

Adjust the potentiometer so that the LED lights up or flickers when you make loud noises.  Connect D0 to a digital input on the Arduino and read it in a loop without a delay, and change your LED state depending on whether the digital input is high or low.



The circuit isn't really an audio amplifier.  The LM393 is a comparator - it delivers an on/off signal indicating whether its input is above or below a selected level.