chapter  4
20 Pages

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

United States 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 at the advent of FM radio transmission in the mid-1950s.