how to record and analyze audio in real-time from two channel (stereo)?

I tried the code form "Geoff Hayes" in the page with the following title :"plotting the recorded sound while recording". It is working for one channel but for stereo audio processing when I change the number of the channel from 1 to 2 , I see nothing in the figures. How I should manage the functions to well detect the different samples from 2 channels (without mixing). for example I have to repeat two time this function: recorder = audiorecorder(Fs,24,1)? recorder1 = audiorecorder(Fs,24,1); recorder2 = audiorecorder(Fs,24,2); like this? and the same for the other functions?