How to make audible sound wave on piezzo buzzer?

Other Hardware Audio
2

So after I looked up modulation as it pertains to audio I understand now :smiley:

My new code:(It makes a sin wave but also modulates the pitch really fast up and down.)

void loop() {
 b=b+1; //for the sine wave
 a=a+mod; //for the pitch modulation
 if(a>40){mod=-mod;}
 if(a<1){mod=-mod;}  //these loop modulation back and forth
 c=75*sin(.004*b)+1600+a*5;  //all the numbers added up.
 tone(13,c);
}