The doctored/edited annoying bipolar ravings of demented Mel will never be admissible in a California court.
While it's impossible to predict with certainty what will or will not come in at trial in any California courtroom, you would have to believe it's highly unlikely these tapes come in.
In federal court, it would be clear - the standard is any editions, deletions or changes, makes the tape(s) inadmissible per FRE 901. From what I've read other places, these tapes show clear signs of professional editing and sound mixing, to include fade-ins and fade-outs. This isn't even a close call, and it has nothing to do with all-party consent.
I listened to it. it is obvious that she was setting him up. The emotionless comments she made were cold and calculating.