THE PRESSURE GRADIENT MICROPHONE
The pressure gradient microphone, also known as the velocity microphone, senses sound pressure at two very closely spaced points corresponding to the front and back of the diaphragm. The diaphragm is thus driven by the difference, or gradient, between the two pressures. Its most common form, the dynamic ribbon (diaphragm) microphone, was developed to a high degree of technical and commercial success by Harry Olson of RCA during the 1930s and 1940s and dominated the fields of broadcasting and recording in the US through the mid-1950s. The BBC Engineering Division in the United Kingdom was also responsible for significant development of the ribbon, extending its useful response to 15 kHz ...