Playback speed identification for early shellac records

In the current issue 1/2025 of the VDT magazine you will find a 5-page article by Torsten Ahl (Deutsches Musikarchiv) and Tom Lorenz about finding the correct playback speed for historical shellac records (78 rpm discs).

The article deals with various aspects of determining the correct playback speed of early shellac records. Digitising records from the early 1900s requires specialist knowledge of tuning, the recording mechanism, playback equipment, the physics of acoustic reproduction and historical knowledge of pitch and musical performance.
The choice of the right equalisation curve and playback speed in conjunction with the choice of the right needle plays an important role in obtaining a signal that is as true to the original as possible. Subsequent corrections to the digital levels are possible. However, losses due to incorrect signal extraction cannot be restored.

QUADRIGA products are used for accurate digitisation and precise documentation. In cooperation with the Music Archive at the German National Library (DNB), a customised solution was installed that enables all parameters to be meticulously stored in a specially developed database.

The article has been jointly written by Torsten Ahl, audio engineer (Tonmeister) at Music Archive of the German National Library, describing the task from the user's point of view, and by Tom Lorenz representing Cube-Tec International.