Voices from the Days of Slavery

Building the Digital Collection

Sound Recordings

The sound recordings in Voices from the Days of Slavery: Former Slaves Tell Their Stories were taken from instantaneous disc recordings in the Library's collections or from preservation tapes when original discs were unavailable, except for two interviews originally recorded on cassette tape. The analog audio from the discs and tapes was converted to PCM digital audio and stored in the WAVE file format.

The preservation WAVE files were created at a sampling rate of 96,000 samples per second and 24-bit word length. A two-channel (stereo) file was created to preserve the disc's two groove walls despite the mono content of the original recording.

Three derivative copies of the recordings were created through a batch conversion process. Dual channel WAVE files were created at a sampling rate of 44,100 samples per second and 16-bit word length. MP3 and RealAudio files were created at a constant bit rate of 256 kilobits per second and a sampling rate of 44,100 samples per second.

Surface noise, clicks and pops, and distortion are inherent in the original discs and tapes. These recordings have not been restored and are presented in this manner to allow for maximum playback flexibility.


Five photographs were scanned onsite in the ITS Digital Scan Center at the Library of Congress. All scans were done at 300 dpi resolution.