Treble Twin Tweeter

Treble Twin

Two nominally similar loudspeakers are used, thus giving a larger radiating area. Because the sound from the two speakers is combined, any differences between their responses are evened out. The two loudspeakers are connected electrically in phase and face each other; each also faces a single cone reflector as in the photograph.
This arrangement gives a uniform distribution of sound in the plane at right angles to the loudspeaker and reflector cone axes (this plane is vertical and at right angles to the paper for this photograph). Moreover, the sound is beamed within a few tens of degrees (+20° at 4kc/s) of this plane.
The bracket for mounting this loudspeaker unit on the wall is shaped so as to allow the plane in which the sound distribution is uniform to be made horizontal or vertical, thus giving a choice between uniform or beamed sound in a horizontal plane.

See also the single version, Treble 20.

In questo link sono elencati 23 modelli, di cui 17 con immagini e 1 con schemi.
Elenco delle radio e altri apparecchi della Magnum (brand) Burne-Jones & Co. Ltd.; London