Binaural Beats, outputting L & R tracks

Hi, I'm trying to create a binaural beat in AA. When I put the two tones on separate tracks and pan one Left and one Right, I see this reflected in the master levels as would be expected.  However, when I listen to the output with headphones I still hear the L track on the R side and vise versa.    

The goal is to hear only the L channel tone in the left phone and the R channel tone on the right phone.  

I'm using Audition CC and a Macbook pro.  Any help would be greatly appreciated.  

Thaddaeus