adio generator program

I am doing research into the effects of binaural beat and high frequency sound. The preliminary work has been done and the results are promising. Unfortunately, to complete the tests I need to obtain new software that will do the required job and I have been having difficulty finding software that has the frequency range that I need.

I am trying to find an audio generator program that will generate a minimum of two tones at the same time, each tone set at a different frequency, one tone each to right and left speakers. Both tones must be as accurate as possible (to a 10th of a hz) and be able to be set anywhere between 500hz and 20khz.

Can you put me on to a program that will meet my needs?