CSCore: Detect different sounds

Question

I'm trying to detect a few sounds that get played. There are about four sounds of different pitches. I'm using cscore something like the following...

using (WasapiCapture capture = new WasapiLoopbackCapture())
{
    capture.Initialize();

    using (WaveWriter w = new WaveWriter(stream, capture.WaveFormat))
    {
        capture.DataAvailable += (s, e) =>
        {                
             w.Write(e.Data, e.Offset, e.ByteCount);
        };
        capture.Start();

however I can't figure out how to detect the different sounds. they are known unique sounds and I just need to distinguish between them. I was thinking of calculating pitch but not sure that is the best way.

does anyone have any ideas or know how I can calculate the pitch?