Hi,

In the following simple sound wave simulation the compression lags behind the wave slightly, by about 1/8 of a wavelength. Is there any smple way to correct this? I've tried but only been able to move the wave left a bit but that's not correct.

1. int numDots = 400;
   
2. int amplitude = 30;
   
3. float frequency = PI/30; //
4. float increment = 1;
   
5. float xPos, xPosLine;
   
6. float vel = 0.01;
   
7. float xIncr = (width-50-amplitude)/numDots;
   
8.  int[]ArrayX = new int[numDots];
   
9. int[]ArrayY = new int[numDots];
   
10. float[]XsinVal = new float[numDots];
    
11. float[]angle = new float[numDots];
    
12. void setup() { size (600, 300);
    
13. for (int i = 0; i < numDots; i++) {
    
14. ArrayX[i] = (int) random(50, width-amplitude);
    
15. ArrayY[i] = (int) random(30, height/2);
    
16.  }
    
17. }
    
18. void draw() { frameRate(24);
    
19.  background (33, 204, 232);
    
20. noStroke();
    
21.  fill(24, 35, 234);
    
22. for (int i = 0; i < numDots; i++) {
    
23. XsinVal[i] = sin(angle[i])*amplitude;
    
24. ellipse(ArrayX[i] + XsinVal[i], ArrayY[i], 3, 3);
    
25.  if (xPos > ArrayX[i]) {
    
26.  angle[i] += frequency;
    
27. }
    
28. ellipse(ArrayX[i], XsinVal[i] + 230, 3, 3);
    
29.  stroke(250, 0, 0);
    
30.  fill(0);
    
31. ellipse(xPos, 100, 3, 3);
    
32. noStroke(); fill(0);
    
33. xPos += vel;
    
34. fill(24, 35, 234);
    
35. }
    
36. }
    
37. boolean bStop;
    
38. void keyPressed() {
    
39. bStop = !bStop;
    
40. if (bStop) noLoop();
    
41. else loop();
    
42. }
    

Thanks,

Shane