Microphone types
sound moves a cone; the coil on it moves in a magnet’s field
sound changes the gap between diaphragm and plate, charged by a voltage
a thin, pleated metal ribbon moves in the gap of a magnet
Dynamic
A coil on the diaphragm moves in a magnet's field. Rugged, needs no power, and takes very loud sources, but gives a lower output (more preamp gain) and less detail in the highs. Stage vocals, guitar amps, drums.
Condenser
U 87 Ai, cardioid
KM 184
The diaphragm and a fixed plate form a charged capacitor; sound changes the gap, and so the voltage. More sensitive and detailed, and reaches higher; needs phantom power (48 V).
- Large diaphragm (about 1″): lower self-noise and a fuller sound; the classic studio vocal mic. Its pattern changes more with frequency (in the drawing), so sound from the sides or back is coloured.
- Small diaphragm (about ½″): more neutral, with nearly the same pattern at all frequencies; for acoustic instruments, overheads, and stereo pairs.
the film keeps its charge; the tiny amplifier still needs power
Electret condensers (of any size) have their charge built into the material, so the capsule needs no polarising voltage. Like every condenser, they still have a tiny amplifier behind the capsule that needs a little power: phantom power, a battery, or a recorder's “plug-in power”.
Ribbon
A thin metal ribbon hanging in a magnetic field; naturally figure-8. Its highs roll off gently from about 8–10 kHz, softening sibilance and cymbals, hence “smooth” or “warm”. Low output (needs a quiet, high-gain preamp), and delicate: keep it out of wind and plosives.
Most ribbons are passive and don't need phantom power; with a correctly wired cable it can't reach the ribbon anyway. But a faulty cable, or plugging in while phantom is on, can jolt the ribbon and stretch it, so switch phantom off before connecting one, especially an older one. Newer active ribbons have a built-in amplifier and do need phantom power.
Next: Polar patterns