R&D Report 1966-28 : The design of a low-frequency unit for monitoring loudspeakers. H.D. Harwood
The present state in the design of low-frequency loudspeaker units is reviewed and the areas where improvement is desired are indicated. Experimental details are given leading to the design of 12 in. (305 mm) unit incorporating a vacuum-formed cone of toughened polystyrene with a p.v.c. (poly-vinyl chloride) surround and it is shown by objective and by listening tests that this design is superior to existing units. An analysis of the price indicates that the new unit should not cost any more than those at present in use.