诺迪奥音量变化

class Sound
{
    private NAudio.Wave.BlockAlignReductionStream stream = null;
    private NAudio.Wave.DirectSoundOut output = null;
    private string fileName;
    public Sound(string fileName)
    {
        this.fileName = fileName;
    }
    public void PlaySound()
    {
        if(fileName.EndsWith(".mp3"))
        {
        NAudio.Wave.WaveStream pcm = NAudio.Wave.WaveFormatConversionStream.CreatePcmStream(new NAudio.Wave.Mp3FileReader(fileName));
        stream = new NAudio.Wave.BlockAlignReductionStream(pcm);
        }
        else if (fileName.EndsWith(".wav"))
        {
            NAudio.Wave.WaveStream pcm = new NAudio.Wave.WaveChannel32(new NAudio.Wave.WaveFileReader(fileName));
            stream = new NAudio.Wave.BlockAlignReductionStream(pcm);
        }
        else throw new InvalidOperationException("Not a correct audio file type.");
        output = new NAudio.Wave.DirectSoundOut();
        output.Init(stream);
        output.Play();
        output.Volume = 0.5f;
    }
    public void Volume(float vol)
    {
    }
    public void PausePlay()
    {
        if (output != null)
        {
            if (output.PlaybackState == NAudio.Wave.PlaybackState.Playing) output.Pause();
            else if (output.PlaybackState == NAudio.Wave.PlaybackState.Paused) output.Play();
        }
    }
    public void Pause()
    {
        if (output != null)
        {
            if (output.PlaybackState == NAudio.Wave.PlaybackState.Playing) output.Pause();
        }
    }
    public void Play()
    {
        if (output != null)
        {
            if (output.PlaybackState == NAudio.Wave.PlaybackState.Paused) output.Play();
        }
    }
    public void DisposeWave()
    {
        if (output != null)
        {
            if (output.PlaybackState == NAudio.Wave.PlaybackState.Playing) output.Stop();
            output.Dispose();
            output = null;
        }
        if (stream != null)
        {
            stream.Dispose();
            stream = null;
        }
    }
    public bool Over()
    {
        if (stream.Position == stream.Length)
            return true;
        return false;
    }
    public void Loop()
    {
        if (Over())
        {
            stream.Position = 0;
            output.Play();
        }
    }

真的不知道这里有什么问题，我很高兴得到帮助，我正在尝试更改输出音频的音量。当我编译此代码时，我在output.volume = 0.5中出现错误。错误是：

设置DirectSoundOut不支持的音量，请改为调整WaveProvider上的音量。