private void StartListening()
{
int sampleRate = 6000;
int fftSize = 1 << (9 + cbFftSize.SelectedIndex);
int stepSize = fftSize / 20;
pbSpectrogram.Image?.Dispose();
pbSpectrogram.Image = null;
listener?.Dispose();
listener = new Listener(cbDevice.SelectedIndex, sampleRate);
spec = new SpectrogramGenerator(sampleRate, fftSize, stepSize);
pbSpectrogram.Height = spec.Height;
pbScaleVert.Image?.Dispose();
pbScaleVert.Image = spec.GetVerticalScale(pbScaleVert.Width);
pbScaleVert.Height = spec.Height;
}