GB215761A - Improvements in the art of recording and reproducing sounds - Google Patents

Abstract

215,761. Dyer, F. L. May 7, 1923, [Convention date]. Record tracks, form of; electric sound-boxes; sound-boxes, supporting; indicating, parts of records.-Relates to records from which sound is reproduced electrically by means of a microphonic sound-box. The record is made with the sound groove of substantially smaller width, amplitude,. and pitch than ordinary. The proportions are, however, the same as usual, and the surface speed, both in recording and reproducing, is also proportionally reduced. By this means the capacity of the record is greatly increased. For example, by making a groove with a width of 0.001 inch and a pitch of 0.002 inch, running the recording turntable at a speed of 16 revolutions per minute, a record is obtained which, if of standard size, may have a duration of more than an hour. The necessary reduction in amplitude of the recorded vibrations' may be effected in various ways, preferably by suitably adjusting the leverage of the cutting-stylus arm. In reproducing, a very light microphonic sound-box is used. Thecurrent variations caused by the operation of the stylus on the microphone may actuate a telephone directly, or, through one or more amplifiers, may work a loud-speaker. The records may be either of the lateral-cut or hill-and-dale type, the groove in the latter case being preferably made with a wedge-shaped cutter. The Figures show a suitable form of microphonic reproducer and the means for mounting it. The needle 4 is carried by a bar 10 which is pivoted in a casing 12 and is controlled by an adjustably stretched wire 14, The microphone, actuated by the bar 10, and' comprising carbon granules 16 and buttons 17, is arranged as shown. An arm 19 carries the reproducer, and is mounted on pivots 20 in a ring- 21 which is arranged on a vertical pivot 22. A counterbalancing spring 23 acts on the arm 19. Preferably a pointer 25, moving over a scale, is attached to the ring 21, and serves to enable, the needle to be placed on any desired point of the record. An electromotor, adapted to run at the. required slow speed, may be operated, for driving the turntable, from a storage battery or lighting circuit. The whole mechanism may be compactly stored, together with the telephone batteries, in a case having a hinged front in addition to the lid. The Specification as open to inspection under Sect. 91 (3) (a), states also that direct soundreproduction from the records may be effected by means of a. sound-box having a small sensitive diaphragm, in conjunction with listening-tubes. This subject-matter does not appear in the Specification as accepted.