How to adjust microphone gain from C# (needs to work on XP & W7)

Question

First, note that I know there are a few questions like this already posted; however they don\'t seem to address the problem adequately. I have a C# application, with all th

Answer 1

I tried doing exactly this a while ago when I was writing .NET Voice Recorder using NAudio, and found it extremely hard. You probably have to end up writing two lots of code, one for XP and one for Vista/Win 7. I am using NAudio for the mixer interop.

This is what I ended up with (still doesn't work everywhere)

    private void TryGetVolumeControl()
    {
        int waveInDeviceNumber = waveIn.DeviceNumber;
        if (Environment.OSVersion.Version.Major >= 6) // Vista and over
        {
            var mixerLine = new MixerLine((IntPtr)waveInDeviceNumber, 0, MixerFlags.WaveIn);
            foreach (var control in mixerLine.Controls)
            {
                if (control.ControlType == MixerControlType.Volume)
                {
                    volumeControl = control as UnsignedMixerControl;
                    MicrophoneLevel = desiredVolume;
                    break;
                }
            }
        }
        else
        {
            var mixer = new Mixer(waveInDeviceNumber);
            foreach (var destination in mixer.Destinations)
            {
                if (destination.ComponentType == MixerLineComponentType.DestinationWaveIn)
                {
                    foreach (var source in destination.Sources)
                    {
                        if (source.ComponentType == MixerLineComponentType.SourceMicrophone)
                        {
                            foreach (var control in source.Controls)
                            {
                                if (control.ControlType == MixerControlType.Volume)
                                {
                                    volumeControl = control as UnsignedMixerControl;
                                    MicrophoneLevel = desiredVolume;
                                    break;
                                }
                            }
                        }
                    }
                }
            }
        }

    }