ahhh, thats the beauty of modern technology.
What we need will just be the basic one track of fart sound. The rest can be through vst plugins, to alter the octave. With that, we can achieve a chromatic scale of fart. The next development wud be sorting out the various pitch, putting in place, using more plugins, to further manipulate the sound. What we have, can be really beyond imagination for what a basic track of fart can give us in the first place.