Difference between revisions of "Microphones"
Revision as of 18:52, 31 January 2010
There are many different types of microphones: Dynamic, condenser, carbon, piezoelectric, and even more more exotic types. The two types of microphones that are the most common by far, are dynamic and condensor microphones.
Dynamic microphones work pretty much like a loudspeaker. The air affects a small membrane attached to a coil suspended in a magnetic field. When the air vibrates, the movement causes the induction of electricity, which then simply needs to be amplified using a designated microphone amplifier.
The typical properties of the dynamic microphone is it's ability to handle rather loud sounds and being robust and sturdy. They also don't make too much rumble when being moved while recording. This is why they're popular for stage use, singing live and generally situations where there's a lot of movement.
They also tend to pick up the local sound much more than ambient sound. This makes them handy when there's a lot of background noise from the surroundings. They are typically less suitable for recording weak ambient sounds.
These work by placing two metal plates very close to each other. By sending a current into one plate, and measuring how much is transfered to the other plate, you can tell the distance between these two plates very accurately. Condensor microphones need phantom power or batteries in order to provide such a current.
The typical properties of condensors are that they are more fragile than dynamic microphones (don't drop them!) They produce rumble much easier if moved or subjected to wind. Because the rather thin metal plate is much easier for the air to move than the membrane+coil design of dynamic microphones, they tend to be more sensitive to even little details. They pick up ambient noise much easier, and typically span over a wider frequency range than dynamic microphones.
Different designs of microphones can make them sensitive in either all directions or certain directions. The most typical types are omnidirectional, cardioid and bi-directional (the figure of 8). You can see the shapes and types on wikipedia.