Super Auditorium Loudspeaker

Super Auditorium Loudspeaker.

The strenuous conditions of PA work will soon reveal any weakness in the mechanical design of a loudspeaker, and many types, even in the larger sizes, which have an adequate reserve of power handling capacity for domestic use develop faults of various kinds if they are pressed into service for use with PA amplifiers.

For this reason, Sound Sales, Ltd., has developed a special loudspeaker for use with their power amplifiers, and although power handling capacity and reliability have been given precedence, the frequency response is also outstandingly good.
The output at 10,000 cycles is at the same level as that in the lower middle register, and there is a gradual rise, but no pronounced peak in the region between 1,000 and 5,000 cycles. The trough at 7,000 cycles was investigated and found to be solely a property of the axial response and could not be detected in listening to the general radiation from the diaphragm.

One of the principal points of failure in highly stressed diaphragms is in the annular surround, which is usually relied upon, together with the centering spider, for support. Parallel action is achieved in the Sound Sales speaker without any assistance from the surround, which is made of flexible woven material. The suspension is shared by a rear centering spider and a series of radial strips which permit an excursion of the coil of approximately ½” at low frequencies. It might be expected that the strips would develop appreciable amplitudes when the applied frequency resonates with their natural period of transverse vibration. This proved to be the case, but the results were entirely negligible as far as the general radiation from the loudspeaker was concerned, as the area of the strips is only a small proportion of the radiating surface.

To make quite sure that damage will not occur as a result of the coil fouling the pole pieces, a gap of one-sixteenth of an inch has been provided, in which the massive magnet coil produces a field of no less than 12,000 lines per sq. cm. The " Super Auditorium " is rated to handle 15 watts when fitted with a proper baffle, and the price is £12 complete with an output transformer.

Wireless World January 8, 1937, Page 46.

Vous pourrez trouver sous ce lien 7 modèles d'appareils, 6 avec des images et 1 avec des schémas.
Tous les appareils de Sound Sales Ltd.; London