In a moving-coil microphone, the diaphragm is attached to a light movable coil that generates a voltage as it moves back and forth between the poles of a permanent magnet.
So even the very early commercially available ribbon microphones had excellent frequency response throughout the nominal range of human hearing (20 Hz to 20 kHz for a young adult).
They are prized for their ability to capture high-frequency detail, comparing very favorably with condenser microphones, which can often sound subjectively "aggressive" or "brittle" in the high end of the frequency spectrum.
A few years later, Dr. Harry F. Olson of RCA started developing ribbon microphones using field coils and permanent magnets.
[15] The German Beyerdynamic M 160 was introduced in 1957, fitted with a smaller microphone element with two 15 mm ribbons combined to create a highly directional pickup pattern.
[17] UK based Stewart Taverner and his company XAudia developed "The Beeb", modifying vintage Reslo ribbon microphones for better tone, performance and increased output.
In 2007, microphones employing ribbon elements made of strong nanomaterials became available, offering orders of magnitude improvement in signal purity and output level.