condenser and dynamic mic ZT

"Condenser" and "dynamic" refer to two ways that a microphone can convert sound into an electrical signal. In a condenser microphone, the diaphragm is a very thin plastic film, coated on one side with gold or nickel, and mounted very close to a conductive stationary back plate. A polarizing voltage is applied to the diaphragm by an external power supply (battery or phantom power) or by the charge on an electret material in the diaphragm or on the backplate charging it with a fixed static voltage. The diaphragm and back plate, separated by a small volume of air, form an electrical component called a capacitor (or condenser). The capacitance between these two plates varies as the freely suspended diaphragm is displaced by the sound wave. When the diaphragm vibrates in response to a sound, it moves closer to and farther away from the back plate. As it does so, the electrical charge that it induces in the back plate changes proportionally. The fluctuating voltage on the back plate is therefore an electrical representation of the diaphragm motion. The dynamic (moving-coil) microphone is like a miniature loudspeaker working in reverse. The diaphragm is attached to a coil of fine wire. The coil is mounted in the air gap of the magnet and is free to move back and forth within the gap. When the sound wave strikes the diaphragm, the diaphragm vibrates in response. The coil attached to the diaphragm moves back and forth in the field of the magnet. As the coil moves through the lines of magnetic force in the gap, a small electrical current is induced in the wire. The magnitude and direction of that current is directly related to the motion of the coil, and the current then is an electrical representation of the sound wave. Condenser microphones typically have a wide-range frequency response and excellent transient response, while dynamic microphones typically do not. There are exceptions. Condenser microphones' frequency response tends to be uniform, while dynamic microphones' typically is not. There are exceptions. Condenser microphones require an external power source (phantom power or battery) while dynamic microphones do not. Condenser microphones are easy to miniaturize, while dynamic microphones cannot be miniaturized. Condenser microphones are typically used on acoustic instruments and studio vocals. Dynamic microphones are typically used on guitar amps and drums, and for vocal sound reinforcement.

Tip #2: Microphone Polar Patterns (also called pickup patterns or directional patterns) A polar pattern is a graph of a microphone's sensitivity vs. the angle of the incoming sound wave. The farther from center a point on the graph is, the stronger is the mic signal at that angle.   Omnidirectional: Picks up equally in all directions.   Half-omnidirectional or hemispherical: Picks up equally over a 180 spherical angle. This is the pickup pattern of PZMs. All of the following patterns are considered unidirectional because they pick up mainly in one direction.   Cardioid: “Heart-shaped” pattern that offers maximum rejection (null) at the rear of the microphone.   Supercardioid: Has a narrower pickup pattern than cardioid, but also has some rear pickup. Note that there are two nulls of maximum sound rejection.   Hypercardioid: Has a narrower pickup pattern than supercardioid, but also has more rear pickup than supercardioid. Note that there are two nulls.   Half-unidirectional: The pickup pattern of PCC microphones. Bidirectional (figure-eight or cosine): Picks up mainly in two directions (in front of and behind the mic) and rejects sound from the sides. Traits of Different Polar Patterns Omnidirectional All-around pickup Most pickup of room reverberation Not much isolation unless you mike close Low sensitivity to pops (explosive breath sounds)   No up-close bass boost (proximity effect) Extended low-frequency response in condenser mics. Great for pipe organ or bass drum in an orchestra or symphonic band. Lower cost in general Unidirectional (cardioid, supercardioid, hypercardioid, hemispherical, half-cardioid, half-supercardioid) Selective pickup Rejection of room acoustics, background noise, and leakage Good isolation--good separation between recorded tracks Up-close bass boost (except in mics that have holes in the handle) Better gain-before-feedback in a sound-reinforcement system Coincident or near-coincident stereo miking Broad-angle pickup of sources in front of the mic Maximum rejection of sound approaching the rear of the mic Supercardioid Maximum difference between front hemisphere and rear hemisphere pickup (good for stage-floor miking) More isolation than a cardioid Less reverb pickup than a cardioid Hypercardioid Maximum side rejection in a unidirectional mic Maximum isolation--maximum rejection of reverberation, leakage, feedback, and background noise Bidirectional Front and rear pickup, with side sounds rejected (for across-table interviews or two-part vocal groups, for example) Maximum isolation of an orchestral section when miked overhead Blumlein stereo miking (two bidirectional mics crossed at 90 degrees)