There is a company I have used in the past to decipher multi party litigation tapes which are taped under non-optimal conditions (no omnidirectional microphone and a boardroom full of people who need to be identified as individual speakers). It is not cheap. The company that used to do it for my firm was called The Fitch Group in NYC. I would not think it worth your time unless it is being used in court but it is more than possible.