Playback Equipment
Playback Equipment and Procedures
The aim of preservation copying is to obtain the highest quality, most accurate representation of the aging original recording possible. For this reason preservation work at Berea is done with professional-level playback equipment that is properly calibrated and maintained. Equipment used in the archive’s sound preservation studio which is specially designed for critical listening, include a Studer A807 for open reel tapes, a Tascam 122MkIII for audiocassettes, and specialized turntable, styli, and phono preamp for disc recordings.
There are several sets of technical procedures necessary for successful preservation copying of archival sound recordings. Among these are basic audio engineering methods along with techniques essential to optimal, accurate playback of aging tapes and discs.
The use of appropriate playback procedures makes a measurable, significant difference in achieving the most accurate representation possible of the original recording. Included among these procedures for analog tapes are visual inspection, slow winding, replacing slotted reels, acid-free paper leaders, proper tape track configuration and playback speed, playback head azimuth adjustments and reproduction alignments. All disc recordings are properly inspected, cleaned, and have the proper stylus, phono eq curve, and channel balance prior to playback transfer.
Analog to Digital Conversion
For preservation, analog-to-digital conversion (ADC) should be handled by a converter separate from the computer, according to best practices document, IASA TC-04 Guidelines on the Production and Preservation of Digital Audio Objects. The associated sound card should then be capable of passing a digital stream without modification.
Berea Sound Archives uses a Mytek Digital USA Stereo96 ADC/DAC in tandem with a Lynx Studio Technology L22 PCI interface card. Steinberg WaveLab 6 captures the AES format digital signal as a high-resolution, 24-bit, 96 kHz PCM BWAV file. A monitor controller system allows for audio monitoring of pre- and post-digital conversion signal to guard against introduction of digital artifacts. The entire signal chain, both balanced analog and AES digital, uses Monster Cable Prolink interconnects.
