Recording microphones have one job; to convert acoustic energy into an electrical signal that can be amplified and recorded. There are many different mic styles each suited for different applications. When setting up the studio for a session, the mic is usually the first device considered, and most studios have an extensive inventory of these sonic tool.
Recording Microphone Types
There are three different types of recording microphones used in a studio; each is characterized by the method used to change the vibrations of the diaphragm into an electronic signal.
Dynamic mics are the most common type of home recording microphones and are often used on stage. They operate on a relatively simple electromagnetic principle; the diaphragm is connected to a movable voice coil and when the diaphragm vibrates, the coil moves which alters the magnetic flux and causes current to flow, hence they are often called moving-coil dynamic mics.
The dynamic microphone requires a minimum of electronic circuitry and therefore results in a durable microphone that requires little more than commonsense handling and care.
Ribbon Mics are a popular choice for recording microphones. They operate similar to the dynamic mic, however, they use a thin metallic ribbon in place of the diaphragm and voice coil. Ribbon mics have excellent transient response, and they are famous for their warm sound.
However, the older ribbon mics are sensitive to gusts of wind and high acoustic pressure and for that reason were not suitable for outdoors.
Over the past several decades, certain microphone manufacturers have been miniaturizing and improving the operating characteristics of ribbon mics. The newer ribbon mics have a more durable design with additional filters added to reduce the ribbon’s sensitivity making them more suitable for outdoor and handheld use.
Condenser Mics are the most commonly used as recording microphones in the studio for vocals, acoustic instrument, an almost everything else, however, they are more delicate than dynamic mics and more expensive.
Basically, in this type of mic the diaphragm is suspended over a parallel back plate, forming a capacitor. As the diaphragm vibrates, the voltage across the capacitor varies, producing an electric signal, which is then amplified by an internal preamp.
Recording Microphone Response Patterns
Recording microphones are also classified according to their directional response patterns, which reflect their ability to pick up sound within a 360 degree radius.
Omnidirectional recording microphones are generally not used for live performances because they pick up sounds coming from all directions. However omni mics are generally less susceptible to wind and breath noise and have a tendency for a relatively flat frequency response with no pronounced peaks, which can help avoid feedback.
Bidirectional, a.k.a. Figure 8, recording microphones are more sensitive to sounds from the front and rear equally well, while rejecting any sound that strikes it from the side, making it well suited for miking two sources, i.e. two singers facing each other or to capture room ambience when taping back up vocals or amplified guitars.
Directional recording microphones respond best to sounds coming from directly in front of the mics capsule. In most cases, this mic will reject any sound coming from the side or from the rear.
Cardioid recording microphones exhibit a heart shaped response pattern, in other words, this mic will give you full response when pointed at or slightly to the side of the source. These are excellent multi-purpose studio mics since they can be used as close mics to isolate an instrument, while still retaining a wide enough field of response to pick up the ambiance of a room.
Supercardioid recording microphones are often used in live performances because they reject more sound from the sides, while the frontal field extends a full 180 degrees, which make it very useful for horn sections and multi-voice backing vocals.
Dynamic recording microphones handle high volume levels from musical instruments and amplifiers and are best suited for guitar amplifiers, drums and vocals…
Ribbon recording microphones, known for their ability to capture high frequency detail, use a thin metal ribbon placed between the poles of a magnet and generates voltages by electromagnetic induction.
Recording Microphone Preamplifier
A recording microphone preamp, short for preamplifier, is an electronic device used in the first stageof amplification to boost the low-level signal to about line level.