iTeadstudio sound sensor - threshold stuck at 600..?

Hi,

I’m a little bit new to Arduino, and while I was testing out my brand new iteadstudio microphone with an Arduino UNO R3, I just couldn’t do anything with it.

#include <NewPing.h>

void setup() {
Serial.begin(9600);
}

void loop()
{
int sensorValue = analogRead(A0);
Serial.println(sensorValue);
delay(200);
}

Here’s my code. Pretty simple isn’t it ?

But when I open the serial monitor, I always get numbers around ~620. If I make a noise, either it won’t change or it’ll go crazy (20, 532, 1080 etc. gave random numbers but I can copy/paste a bit if needed). I tried to wire it to a pair of headphones just to listen to what the mic was “hearing” : statics…

I would assume the microphone is just not working and that I might have to change it, but I wanted your opinion on this, if it isn’t to much to ask.
Just so you know, I checked and re-checked my wiring over and over but nothing changes…

Let me know if you need any more informations, and thank you in advance !