Playback Losses and the Design of Wide-Band Phonograph Pickups
James V. White · The Journal of the Acoustical Society of America · 1971
Mechanical playback losses in phonographs fall into two categories, termed pickup loss and scanning loss. Pickup loss is due to resonances in the mechanical system formed by the tone arm, pickup, and compliant groove walls. Scanning loss, on the other hand, arises because of the finite areas of contact between the stylus and each of the groove walls. Pickup loss can be reduced to arbitrarily low levels by making the driving-point impedance of the stylus much smaller than the groove impedance. Scanning loss, however, can be reduced only by reducing the effective interaction, or scanning, area between the stylus and the groove wall. The rational design of wideband phonograph pickups will be discussed in light of our present understanding of these losses.