Speakers for the All-Electric

Radio Record, Volume III, Issue 10, 20 September 1929, Page 13

Speakers for the All--Electric

Modern Improvements With the rapid improvement of. the radio receiver, its accessories likewise improve. Where both radio and audio stages of a set can reproduce almost without .distortion, the music from either the.air or gramophone set, a suitable speaker has to be to‘ complete. There are: roughly three types of the. hor, the magnetic tone.and dynamic ‘tone; Where a great deal: of volume -‘has to be handled, the quality main‘tained, there is only one speaker that ean do the job efficiently, and that is the dynamic tone, ‘although several . ‘types of a megnetic | cone come very near to it. €- ' The .horn speaker is very sensitive and very, pleasing on certain types of sets, and has not entirely disappeared from the radio world. Its popularity, " however, is not increasing, though it is ‘sometimes discarded when it -_ still remain. ‘Magnetic cones. have been improved ‘yapidly, and some of the now existing models are very like the dynamic. They ‘give a. good overall reproduction, and haye the advantage of being light and ie. tpinsportable. Another advantage they -Hlave no need for a baffle or baffle cabinet. The dynamic cone is universally recognised as the perfect speaker, although, really, it is not perfect, as far as power utilisation is concerned.

It has been pointed ont in -another article that only a very small percentage of the power fed from the power valves can be finally utilised as sound by the speaker. This means that there is a big waste. The listener and the technician do not notice this (in fact it is unnecessary to notice it) when a good speaker is heard. Adequate power can be provided, especially with a good push-pull amplifier to feed any speaker. Where the amplifier and speaker are matched ‘almost perfect results obtain. Modern power amplifiers with. low impedance valves require for their best By esults a speaker with a low impedance, and this is most often met with in the dynamic. It has been explained many times that there are several types of this speaker, two of which will become more popular than the third. The hundred volt winding and the 230-volt AC mains unit will be used in preference to the 6-volt. This, of course, is inevitable with the disappearance of the battery charger and the accumulator. Modern dynamic speakers no longer cause a preponderance of the base and an attenuation of the treble. Reproduction is round and even, having a definite proportion of both sides of. the musical scale.