1、新建一fla文件soundSpectrum.fla

2、新建一soundSpectrum.as文件，并与soundSpectrum.fla关联

soundSpectrum.as：

package 

{
import flash.display.Sprite;
import flash.events.*;
import flash.media.Sound;
//混音器类
import flash.media.SoundMixer;
//声音通道类
import flash.media.SoundChannel;
import flash.net.URLRequest;
import flash.utils.ByteArray;

public class SoundSpectrum extends Sprite
{
[Embed(source = "mp3/kate havnevik - solo.mp3")]
private var soundClass:Class;
private var sChannel:SoundChannel;
private var bArray:ByteArray = new ByteArray();
private var Ary:Array;
private var n:Number = 0;
//初始化函数
public function SoundSpectrum()
{
sound = new soundClass();
//播放
sChannel = sound.play();
this.addEventListener(Event.ENTER_FRAME,showBar);
}

/**显示频谱条**/
private function showBar(event:Event)
{
n = 0;
//清除绘图
this.graphics.clear();
//将当前声音输出为ByteArray;
SoundMixer.computeSpectrum(bArray,true,0);
for (var i=0; i < 352; i=i+16)
{
//在ByteArray中读取一个32位的单精度浮点数
n = bArray.readFloat();
//这个实际作用是把n扩大一下
var num:Number = n * 360;
//设置线条样式,颜色绿色,宽度10,透明度100
this.graphics.lineStyle(10,0x99FF00,100,false,"noSacle","none");
//移动到x坐标50+i,y坐标200的位置;
this.graphics.moveTo(8+i,200);
//向上画图;
this.graphics.lineTo(8+i,200-num/3);
}
}
}

}

Ctrl+Enter效果：