Having recently attended DAFx, for my 4th year, I was presenting my paper on Objective Evaluation of Synthesised Environmental Sounds. 

The basic premis of the paper, is that we can computational measure how similar two sounds are using an objective metric. This objective metric can be evaluated using an iterative resynthesis approach. And a given similarity score can be evaluated through comparison to human perception.

I hope this made sense, but if not please get in touch and I would be happy to explain further. The paper will be available on the DAFx Website shortly.