rtaudio

I use Rtaudio library and I would like to implement an audio program where I can control the panning (e.g. shifting the sound from the left channel to the right channel). In my specific case, I use a duplex mode (you can find an example here: duplex mode ). It means that I link the microphone input to the speaker output. Should I apply a filter on the output buffer? What kind of filter? Can anyone help me? To reduce the signal on the left, simply multiply every sample on the left by a number less than or equal to 1, let's call it l. Similarly for the right, we'll call that number r. Generally