如何使用C＃计算音频增益？

Question

我有以下低通滤波器c＃代码，这会降低音频功率，使音量非常低。我希望通过乘以增益来增加它的功率/放大它。我想知道在滤波后我应该乘以多少增益以保持音频强度。

这是我的代码：

    public MyFilter(ISampleProvider sourceProvider,int cutOffFreq)
    {
        this.sourceProvider = sourceProvider;
        this.cutOffFreq = cutOffFreq;

        channels = sourceProvider.WaveFormat.Channels;
        filters = new BiQuadFilter[channels];
        CreateFilters();
    }

    private void CreateFilters()
    {
        for (int n = 0; n < channels; n++)
            if (filters[n] == null)
                filters[n] = BiQuadFilter.LowPassFilter(44100, cutOffFreq, 1);
            else
                filters[n].SetLowPassFilter(44100, cutOffFreq, 1);
    }

    public WaveFormat WaveFormat { get { return sourceProvider.WaveFormat; } }

    public int Read(float[] buffer, int offset, int count)
    {
        int samplesRead = sourceProvider.Read(buffer, offset, count);

        for (int i = 0; i < samplesRead; i++)
            buffer[offset + i] = filters[(i % channels)].Transform(buffer[offset + i]);

        return samplesRead;
    }