Disk Recording and Reproduction

In 1878, Thomas Alva Edison built the first working phonograph but it remained for Berliner to bring together the various ideas which charted its future course. Major electroacoustical advances responsible for vast improvement in disk recording and reproduction took place during and after World War I, and into the twenties, such as the concept of mechanical and acoustical impedance, "electrical recording," folded exponential hom, and electromechanical pickup. Further advances occurred in the thirties: utilization of Rochelle salt crystals in phonograph pickups, the use of negative feedback in recording, as well as significant contributions to the theory of groovestylus relationships. The end of World War II marked the beginning of "high fidelity" as a household word including developments of improved magnetic pickups, advances in measurements and calibrations, utilization of barium titanate transducers and improved record materials, and culminating with the introduction of longplaying records. The fifties saw an ever widening use of magnetic tape for mastering, development of hot-stylus and variable-pitch recording techniques, and continued trend toward lightweight pickup design. These improvements, combined with ideas on binaural and stereophonic recording that have been dormant since the twenties and thirties paved the way to the introduction of stereophonic disks in 1957. In the hands of the artist and the composer the advances in disk recording are leading to new art forms as well as to more faithful reproduction of great classics.