Adventure Game Studio

I've included a bit of code in a room which manually animates an object, and plays 'linked' sounds for each frame; it then adjust the volume depending on the players position and closeness to the object.
The sounds are played at full volume for the first second; what should I do to keep the sound consistent?

function SoundDistDS(int x, int y, int radius, int minVolume)
{
  int Volume=0;
  int dx = 610 - x;   //hard coded in pos of darkseeds sign
  int dy = 515 - y;
  int d_squared = dx*dx + dy*dy;

  if(d_squared >= (radius * radius))
    Volume = minVolume;
  else
    Volume = FloatToInt(100.0 - (Maths.Sqrt(IntToFloat(d_squared))/IntToFloat(radius)) * (100.0 - IntToFloat(minVolume)));
   
  return Volume;
}


function PlaySoundDS(int animFrame)
{
  switch (animFrame) {
    case 0: ds_chan=aNeon_1.Play(eAudioPriorityNormal, eOnce);break;
    case 1: ds_chan=aNeon_2.Play(eAudioPriorityNormal, eOnce);break;
    case 2: ds_chan=aNeon_1.Play(eAudioPriorityNormal, eOnce);break;
    case 3: ds_chan=aNeon_2.Play(eAudioPriorityNormal, eOnce);break;
    case 4: ds_chan=aNeon_1.Play(eAudioPriorityNormal, eOnce);break;
    case 5: ds_chan=aNeon_2.Play(eAudioPriorityNormal, eOnce);break;
    case 6: ds_chan=aNeon_1.Play(eAudioPriorityNormal, eOnce);break;
    case 7: ds_chan=aNeon_2.Play(eAudioPriorityNormal, eOnce);break;
    case 8: ds_chan=aNeon_1.Play(eAudioPriorityNormal, eOnce);break;
    case 9: ds_chan=aNeon_2.Play(eAudioPriorityNormal, eOnce);break;
    case 10: ds_chan=aNeon_3.Play(eAudioPriorityNormal, eOnce);break;
    case 11: break;
    case 12: break;
    case 13: break;
  }

  ds_chan.Volume=SoundDistDS(cJulius.x, cJulius.y, 300, 3);
}

function late_repeatedly_execute_always()
{
  //Display("wa %d, yctr %d", wa, yctr);
  wa++;
  if (wa>20) {
    wa=0;
    yctr++;
    if (yctr>13)
      yctr=0;
   
    ViewFrame *vf;
    vf=Game.GetViewFrame(10, 0, yctr);
    oDarkSeedsSign.Graphic=vf.Graphic;
    PlaySoundDS(yctr);
  }
}


function room_Load()
{
  ...
  oDarkSeedsSign.SetView(10);

  wa=0;//global
  yctr=0;//global
...
}

Have you try to use AudioChannel.SetRoomLocation?