A microphone is an example of a transducer, a device that changes sound from one form to another. Sound exists as patterns of air pressure; the microphone changes this into patterns of electric current.
Microphones vary greatly in quality. A top end recording studio microphone may cost thousands and in many cases they are needed for the very best recordings. A variety of mechanical techniques can be used in building microphones. The two most commonly found in recording studios are the magneto-dynamic and the variable condenser designs.
All microphones convert sound energy into electrical energy, but there are many different ways of doing the job, using electrostatics, electromagnetism, piezo-electric effects, or even through a change in resistance of carbon granules. When it comes to microphones used in recording studios, the vast majority of microphones used are either capacitors, electrostatic, or dynamic.
Both types employ a moving diaphragm to capture the sound, but make use of a different electrical principle for converting mechanical energy into an electrical signal. The efficiency of this conversion is very important, because the amounts of acoustic energy produced by voices and musical instruments are so small.
Different types of microphones used in recording studios
In live sound, nearly all the microphones used are dynamics. In the studio, instruments such as drums, electric guitars, and basses are recorded using dynamic microphones. Dynamic microphones have the advantages of being relatively inexpensive and durable, and they don't need a power supply or battery to make them operate.
Dynamic microphones are most effective when working with relatively loud sound sources that do not contain a lot of very high-frequency detail. They are also tough instruments which make them good for recording studios. Another type of dynamic microphone is the ribbon microphone, but this is only used in fairly esoteric recording applications by engineers who appreciate the subtleties of the ribbon sound.
These microphones are comprised of a thin metal ribbon suspended in a magnetic field, and when sound energy is encountered, the electrical signal generated is induced in the ribbon itself rather than in a voice coil. The main advantage of ribbon microphones is their smooth, detailed sound which makes them perfect for studio environment.
Capacitor microphones are more expensive than their dynamic counterparts, and they are also much more sensitive, and can capture high-frequency detail much more accurately. Even though they are relatively efficient like dynamic microphones, capacitor microphones produce such a small electrical signal that they require a special type of built-in preamplifier to bring the signal up to usable levels. Thus they are not fit to be used in live concerts or open air concerts. Capacitors are used mostly in recording studios where there is less noise.
Conclusion
The microphone is a ubiquitous piece of equipment. Found in everything from telephones and computers to recording studios, microphones are part of our daily life. A professional studio will accumulate a varied collection of microphones. The top studios use microphones such as Shure SM58s and 57s, AKG D112s, or Sennheiser 421s. |
