Ribbon Microphone is a dynamic microphone that uses the principle of electromagnetic induction. A ribbon-shaped metal film usually made of aluminum or duralumin is placed between the poles of the magnet. When the film is vibrated by sound, electromagnetic induction And the signal of life.
Since the most common meaning of the English word Ribbon is ribbon, it is often translated into a ribbon microphone. In fact, the original text here does not refer to ribbons, but ribbons.
The aluminum ribbon microphone uses a thin, usually wrinkled or wavy aluminum ribbon film, placed between the two poles of the magnet, the film is parallel to the lines of magnetic force, and both ends are fixed on an insulating frame to extract the induced signal. When the film vibrates with sound waves, the magnetic field lines are cut to generate electromagnetic induction current. The direction of this current is perpendicular to the direction of the magnetic field and the direction of sound wave vibration. Signals can be connected to both ends of the aluminum ribbon film. This signal is very small and has a very low impedance. Because the signal is too small, a transformer is usually built into the microphone to increase the voltage before outputting.
Since both the front and back sides of the film can accept sound waves, the directivity of the basic ribbon microphone is Bi-directional.
The earliest ribbon microphone was invented by German physicists Dr. Walter H. Schottky and Dr. Erwin Gerlach in the early 1920s. They also used this circuit in reverse and invented the earliest ribbon loudspeaker (Ribbon Loudspeaker).
In the early 1920s, Dr. Harry F. Olson of Radio Corporation of America (RCA) began to develop ribbon microphones. In 1931, RCA Company produced the first commercial product of ribbon microphone: RCA PB-31 microphone. It was a major breakthrough in audio technology at that time. The frequency response, sound clarity and realism were significantly better than those of capacitors at the time. The microphone has become the new benchmark for microphones and has caused a major revolution in the record recording industry and broadcasting industry.
A few months later, the 44A, the successor model of the PB-31, was launched in 1932, which was a great success and highly praised, and new models were subsequently launched.
This type of ribbon microphone can often be seen in photos or videos of major broadcast speeches from the 1930s to the 50s.