Sound gets loud in while playing game?

Hi,
I’m making a Slender based game, and I am adding a sound so that when you get the first page it plays some background music. Here is the code that I am using to play the sound (javascript):

#pragma strict

var papers : int = 0;
var papersToWin : int = 8;
var distanceToPaper : float = 2.5;
public var paperpickup : AudioClip;
public var onepage : AudioClip;

function Start() 
{
    Screen.lockCursor = true;
}

function Update() 
{ 
    if ( Input.GetMouseButtonUp(0) )
    {
        var ray = Camera.main.ScreenPointToRay( Input.mousePosition );
        var hit : RaycastHit;
        if ( Physics.Raycast( ray, hit, distanceToPaper ) )
        {
            if ( hit.collider.gameObject.tag == "Paper" )
            {
                papers += 1;
                audio.PlayOneShot(paperpickup);
                Debug.Log( "A paper was picked up. Total papers = " + papers );
                Destroy( hit.collider.gameObject );
            }
        }
    }

    if ( papers == 1 )
    {
        audio.PlayOneShot(onepage);
    }

}

function OnGUI()
{
    if ( papers < papersToWin )
    {
       GUI.Box( Rect( (Screen.width/2)-100, 10, 200, 35 ), "" + papers + " Papers" );
    }
    else
    {
       GUI.Box( Rect( (Screen.width/2)-100, 10, 200, 35 ), "All Papers Collected!" );
    }
}

The part for the music to be played is this part:

        if ( papers == 1 )
        {
            audio.PlayOneShot(onepage);
        }

When I play the game, however, it sounds really weird and strange. Here is what I mean: - YouTube
Also, when I preview the sound that I am using, it sounds normal, as you can see in the video, but once I play the scene, it sounds weird. Can anyone help me with this? Any help is appreciated.
Thanks!

The actual problem here is where you put

if ( papers == 1 )
{
    audio.PlayOneShot(onepage);
}

This is in Update, therefore you are making a sound every frame. to do what you are doing, you need to set up a boolean, so when the papers == 1, play the sound once, then change the boolean so it doesnt play again. Have a look at the footstep script I wrote in V2 .

var playedOnePaperSound : boolean = false;

// UPDATE
if ( papers == 1 && !playedOnePaperSound  )
{
    audio.PlayOneShot(onepage);
    playedOnePaperSound = true;
}