[Extract from John Powers, "The History of Presidential Audio Recordings and the Archival Issues Surrounding Their Use" (1996). Used with permission.]
There are approximately ten hours of recordings from the Truman administration. Few concrete facts are known about these recordings. When Truman became president on April 12, 1945, he inherited the RCA Continuous-film Recording machine that Roosevelt used during the 1940 Presidential election campaign. Although Roosevelt did not use the machine again after his reelection, he did not dismantle it either. His machine was not only still in place, but also still had the same roll of sound scribed acetate film on it--the same roll that contained Roosevelt's recordings. 
Jack Romagna became the white House stenographer in 1941, replacing Henry Kannee. Before leaving, Kannee briefed Romagna on the operation of the RCA recording machine.  Romagna informed Truman about the machine, telling him that the microphone was located in his desk lampshade and the control box was located in his desk drawer. Romagna recalled Truman authorizing him to record his May 23, 1945, press conference, stating that Truman “was curious to know how the machine would perform.”  Truman went downstairs afterward to listen to his recording with Romagna, a Secret Service technician, and Matt Connolly, his appointments secretary. The President's comments to the press came through loud and clear.  After listening to the recording, Truman told those present, “I sure don't want to have anything to do with that!” 
According to Romagna, Truman did not use the machine again, but he did not recall the machine being removed either.  The remaining recordings are very difficult to understand. Philip Lagerquist, the audio-visual archivist at the Truman Library, listened to these recordings extensively. He concluded that most of the recordings contain “long stretches of silence [static] or background noise,” and that, of the ten hours of recordings, only “a few hours of this consists of conversation, either intelligible or unintelligible.”  The recordings include miscellaneous conversations of workmen and members of the White House staff, segments of conversation between Truman and unknown individuals, portions of telephone conversations between Truman and unknown individuals (only Truman's voice was recorded), completely unintelligible conversations, static, and room noise. 
Lagerquist, in researching and listening to the contents of what he heard on the tapes, concluded that Truman's recordings date between 1945 and 1947, with the bulk of the recordings dating from 1945.  Unfortunately, there is no pattern to the recordings. Lagerquist speculates that the recordings were
done at random times and for no discernible reasons. It follows that the recordings were not made as a matter of historical record or to provide the President or his staff with administrative assistance. 
Romagna stated that he would turn on the machine periodically and “practice” using the machine “in case I should be called upon without warning to transcribe something of an urgent nature.” 
There are no records discussing the removal of the RCA machine, and Romagna has no recollection of this occurring. In any event, the machine was removed some time in 1947, when the National Archives acquired custody of the machine and copied the sound scribed film onto acetate discs for transfer to the Roosevelt Library. 
 “Conversations recorded during Truman’s administration,” Kansas City Times, February 9, 1982, p. A-1. See also: Benedict K. Zobrist to Jack Romagna, February 25, 1982, and Romagna to Zobrist, March 7, 1982, Truman Library, Reference File. Originally, the sound scribed acetate film was duplicated by the National Archives onto sixteen 16-inch disks in 1947 and the original film was then destroyed. The discs, containing both Roosevelt’s and Truman’s recordings, were sent to the Roosevelt Library. Eventually, ten of the discs were then sent to the Truman Library in 1973 after it was determined that they were recordings of Truman’s voice. See “The FDR Tapes,” pp. 11-12.
 “The FDR Tapes,” p. 15.
 Romagna to Zobrist, March 7, 1982, Truman Library, Reference File.
 Of the approximately ten hours of recordings, this is the only segment that is entirely audible. Romagna stated in his letter to Zobrist that this was the single occasion during the Truman administration that Romagna operated the machine. Romagna used the switches on the machine to record and ensure that the volume was at the proper level.
 Romagna to Zobrist, March 7, 1982.
 Philip Lagerquist to Benedict Zobrist, February 12, 1982, Truman Library, Reference File. This memo also includes the attachment describing, as best he could, a summary of the contents of each disc recording.
 Romagna to Zobrist, March 7, 1982. Romagna recalled that occasionally Truman would direct him to listen in on a telephone conversation and take shorthand notes. In all cases, Truman would inform the person on the other end that his aide was on an extension and taking notes.
 “The FDR Tapes,” pp. 11-12.