Playing/Recording acoustic signal in matlab to tell difference between 2 sounds
I understand that you want to tell if your second laptop is placed on the left or right (or maybe on the axis) of main node? 

I suggest you then to play the two-tone stereo signal, i.e.: $15\;kHz$ from the left, and $16\;kHz$ from the right speaker at the same time. Assuming that you are going to use sampling frequency of $f_s=41000 \;  \text{Hz}$ and taking the average distance between two speakers in a laptop to be $25\;cm$, you can calculate that the maximum delay between two signals, if the second node is on the right, will be approximately: $\dfrac{0.25}{343}=0.7289\;msec$. This corresponds to $32$ samples at a given sampling frequency. It is therefore a hard task, but still possible. Then after finding the delay between two signals, from its sign you are able to tell which speaker is further away, ergo you are on the opposite side. 

In MATLAB you just need to generate proper signals, given sampling frequency and play them back/record with: MATLAB - Record and Play Audio.

Few problems can arise:


You want to use very high frequencies, and this can be problematic as laptop speakers are usually low-grade gear and they possibly might have some problems- same goes to microphone. Also remember to turn any hardware noise cancellation, spatial enhancements, etc.
Detection of you signal onset could be problematic as the resolution of DFT will be to low. You can also use some kind of correlation detection, but this is a problem for later on.