. The Bell System technical journal . led lateralcut record; that is, a record in which the groove is of constant depthand oscillates or undulates laterally about a smooth spiral. This isthe type used in the Western Electric Company disc record type ofsynchronized motion picture system. Some, but not all of the con-siderations and conclusions might apply to the hill and dale typerecord. It is not the purpose of this paper to consider the relativecharacteristics of hill and dale and lateral wax records. Electromechanical Recorder It is the task of the electromechanical recorder to take power fr
. The Bell System technical journal . led lateralcut record; that is, a record in which the groove is of constant depthand oscillates or undulates laterally about a smooth spiral. This isthe type used in the Western Electric Company disc record type ofsynchronized motion picture system. Some, but not all of the con-siderations and conclusions might apply to the hill and dale typerecord. It is not the purpose of this paper to consider the relativecharacteristics of hill and dale and lateral wax records. Electromechanical Recorder It is the task of the electromechanical recorder to take power fromthe amplifier and drive a mechanical recording stylus. The present- RECENT ADVANCES IN WAX RECORDING 161 day recorder is a highly developed apparatus based on extensiveexperimental as well as theoretical studies. A diagrammatic view isgiven in Fig. 1.^ Recorders which have been supplied by the WesternElectric Company have been designed to operate over a range offrequencies from 30 to 5,500 cycles. A typical frequency characteristic. Fig. 1—Diagrammatic view of the electromechanical recorder. is shown in Fig. 2. The device operates in linear fashion over the range of amplitudes involved in speech and music. As is seen, the response falls off below about 250 cycles. This falling characteristic is necessary in order that the maximum loudness be obtained from a record for a given spacing between grooves without cutting over 2 High Quality Recording and Reproducing of Music and Speech, by J. and H. C. Harrison, presented at 14th Midwinter Convention of theAmerican Institute of Electrical Engineers, New York, N. Y.,^Feb., 1926. 162 BELL SYSTEM TECHNICAL JOURNAL from groove to groove. In order that a lateral oscillation in a groovemay represent constant intensity of sound or a constant energy overa range of frequencies, not the amplitude of the oscillation but thevelocity, which is proportional to the product of the amplitude andthe frequency, must be maintained constan
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