RADIO “IN DEPTH"

Press, Volume XCVII, Issue 28752, 25 November 1958, Page 9

RADIO “IN DEPTH"

8.8. C. Tests Begin

As an citernative to the present system of st' -euphonic broadcasting, which the 8.8. C. has demonstrated experimentally, the corporation’s engineers are now studying new methods of achieving the same end, using only a single transmitter; and it may be along this line, if successfully pursued, that the future of stereophonic broadcasting lies, says the radio correspondent of “The Times.” Its achievement, and the “quality of realism" such a system could give to certain types of programme, would add as much to sound broadcasting as a brush of colour to the television screen.

The 8.8. C. is convinced that the existing stereophonic system, which demands two separate transmission channels, and duplicate receivers in listeners’ homes to simulate the “3-D" effect, is useless as a means of introducing a regular stereophonic sound broadcasting service in Britain. The recent experimental programme, which included the first pi-esentation in Britain of a radio drama in stereophonic sound, was merely one of a series started early this year to provide the public with an opportunity “to experience stereophonic broadcasting." The experiments are also helping the 8.8. C. to understand better some of the purely technical problems in the handling of programmes broadcast, as it were, in depth and breadth. Second Unit

The aim is to develop a new. compatible system using a single transmitter to broadcast sound which can be heard well on a conventional monaural receiver and expanded into the fullness of stereophony by the addition of a second sound reproducing unit. This unit, when commercially developed, might be expected to cost £lO or £l2. Electric and Musical Industries have recently demonstrated their Percival system to the 8.8. C. over a closed circuit at Hayes, and in the corporation’s view it is probably the most promising for further development. The 8.8. C. and E.M.I. are now co-operating to improve its performance.

In principle, the system employs only one channel, carries the signal and a “direction” component at supersonic frequency, which, of course, cannot he heard at the receiving end. A single radio receiver is needed and the signal (music or voice) passes through to the loud-speaker in the usual way, thus satisfying the “single-set listener.” Where stereophonic effect is required the “direction" component is taken away to a separate unit which controls the balance of sound between the conventional radio receiver and a second loudspeaker.