Old radio shows. Bing Crosby. Frank Sinatra. The smooth horn parts on a 1960s record. Almost all of it was tracked through ribbon microphones — the simplest, oldest, and most fragile mic design still in regular use.
A ribbon microphone is the simplest design of any of these. Imagine a tiny piece of corrugated aluminum foil — about half the thickness of a human hair — suspended in the gap between two strong magnets. As sound waves move the foil, it generates a small electrical signal directly. No diaphragm-and-coil, no plates, no power needed.
That “move the foil with sound” design gives ribbons their characteristic figure-8 polar pattern: they pick up sound equally from front and back, and reject sound from the sides.
Ribbon mics roll off the high end naturally. The result is a smooth, slightly dark sound that flatters bright sources like brass, electric guitar amps, and cymbals. They make a screaming Marshall stack sound rich instead of harsh. They’re also fast — they capture transients faster than most condensers — but with a softer top end.