The Jonestown Death Tape
An audio recording made on November 18, 1978, at the Peoples Temple compound in Jonestown, Guyana immediately preceding and during the mass suicide and murder of over 900 members of the cult.
Original Notes:
I acquired the source cassette tape from a schoolmate c. 1979 whose father was an FBI agent
The sound levels were increased as close as possible to clipping when I mastered to CD-R from cassette and then normalized to -18dB average RMS power (loudness) in Sound Forge
An interesting website for further research is the Jonestown Institute which contains transcripts as well as commentary on this and other recordings recovered by the FBI from Jonestown after the mass suicide and murders.