GOODMANS 12 INCH AUDIOM 70 LOUDSPEAKER TWEETER & CROSSOVER UNIT, 1960's

Goodmans High Fidelity twelve inch 20 Watt 15 Ohms loudspeaker. During the 1950's and 1960's High Fidelity (Hi-Fi) was at its peak, the quality of amplifiers such as the Mullard 5-10, see Item A1646, and it's smaller brother the 3-3 were of a high quality and low distortion, these were being built by enthusiasts who would require loudspeaker elements such as these units to get the maximum quality sounds. There is no substitute for size and this Bass speaker would need a cabinet of at least three cubic feet, preferably of triangular shape with a port, or vent, tuned to the speakers resonant frequency, in this case 35 cycles (Hertz). When this frequency was being produced, the air from the port could blow out a candle. This speaker weighs 18lb 4 oz (8.3 Kgs).
It was said at the time, that Wharfedale Ltd, who also made high quality speakers, set up a demonstration consisting of a full orchestra behind one curtain and some of there larger speakers behind another, when an audience was asked which was the real thing, most were confused but the majority chose the speaker system over the orchestra, I have yet to meet with confirmation of this test. See G.A.Briggs ‘Loudspeakers’ first published in 1948.
Together with the bass speaker is Goodmans Trebax 100 tweeter unit, to provide the high frequencies that the large cone cannot produce, it handles anything above four thousand cycles (Hertz) and can so its said ‘lift the large speaker out of the box’ producing an overall range of sounds. An addition of a mid range speaker would be a further improvement.
Today the word Hi-Fi is present on almost all reproducing systems sold, when they are nothing like the quality of systems using these products. The author of this article built his own five cubic foot speakers and is still using them today.
On the bottom right of the picture, is the crossover network required to filter the bass sound from the treble, frequencies lower than 400 cycles (Hertz) would damage the Tweeter unit.
In the 1950’s and 60’s Hertzian waves were termed as cycles per second, today, Hertz is used for frequency measurement.

A1804