 At the time, the company benefited from cutting-edge technical help from NHK Science & Technical Research Laboratories -- a relationship that would continue for many years.In 1947 Mitsubishi produced an adjustable resonance cone, and combined it with the OP magnet to produce the 16 cm P-62 F-type dynamic speaker (the antecedent of the P-610).In the 1940s, practically all speaker diaphragms were constructed from plain paper pasted together into a cone shape.