At the time, Mitsubishi Electric benefited from cutting-edge technical assistance from NHK Science & Technical Research Laboratories -- in a relationship that would continue for many years. In 1947 Mitsubishi Electric produced the adjustable resonance cone, and combined it with the OP magnet to produce the 16cm P-62 F-type dynamic speaker (the antecedent of the P-610), a development still noted today.

In the 1940s, practically all speaker vibration boards were constructed from plain paper pasted together into a cone shape. Mitsubishi Electric's speaker used a special single-cone paper made from a sheet of Japanese washi paper formed into a conical shape, and delivered epoch-making performance. Though it was launched in the fall of 1947 to high acclaim, it was in 1950 that the speaker was formally accepted as a monitor speaker for broadcast use. It was the first step into a market dominated by foreign products. The Diatone brand trademark was registered in September 1946, and the product came to be known as the Mitsubishi Diatone Speaker from 1947.