The most common types of microphones used in recording studio’s are condensers, dynamics, and ribbons. Each one has its own unique traits, which can make it preferable in different circumstances.
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The most basic type is the dynamic. As explained in lesson 3, how sound flows as electricity, this type of microphone is like a speaker, but used backwards to generate electricity from the sound waves in the air.
It will consist of a diaphragm that vibrates from the sound waves, which is attached to a coil of wires housed within a magnet.
They can come in any polar pattern, but most dynamic microphones on the market are either cardioid or super cardioid.
Dynamic microphones are the most versatile, and tend to be a good “general all purpose” style of microphone. They usually sound good on pretty much anything, but there are many specific applications which a condenser or a ribbon will sound even better.
Dynamic microphones tend to be less sensitive than condensers. For this reason they are the most common choice for hand held vocal microphones, as they are less prone to bleed from other instruments and feedback. They are also a common choice for very loud spl sources, such as close up drum mics, guitar cabs, and loud vocalists.
The drawback of dynamics is that they tend to have a low output, so don’t work very well for quieter sources, and generally have lower fidelity than condenser microphones.
Condenser microphones are probably the most popular type in a recording studio environment. They are capable of very high fidelity, and are extremely sensitive.
Due to this heightened sensitivity, they are less suitable in rooms with poor acoustics, sources with very loud volumes, live settings where other sounds and feedback are issues.
But, in a well treated studio, they sound fantastic on most sources, such as acoustic instruments and vocals. They can be placed about a foot or 2 away, and they get a nice, up close, kind of sound.
The condenser microphone picks up sound from a capsule which consists of 2 plates that are close together and given an electric charge. These 2 plates act as a capacitor, and one of them will be the diaphragm which vibrates with the sound. As this plate vibrates, it’s distance from the other plate changes, which causes fluctuations in the voltage.
These voltage fluctuations are extremely tiny, and need to be amplified so they can be at useable level.
For this reason, All condenser microphones have a built in amplifier, and require a power source to drive this amplification. Many also use this power source to supply the charge the capsule needs, however some designs, called a back electret, use magnets instead. Some condensers take batteries to power the amplification circuit, however the most common way to supply this power is through Phantom Power.
Phantom power is 48 volts of dc current, provided from the preamp, and sent into the microphone through the microphone cable. The single microphone cable is capable of carrying the phantom power, and simultaneously transmitting the audio from the mic to the preamp, without any impurities.
Ribbon microphones are not used as much, as they are generally lower fidelity, and have a very weak signal output which requires a lot of gain. Because they need more gain, noise from the preamp also gets introduced into the signal.
However, with a high quality preamp, the ribbon microphone can sometimes achieve a warm and beautiful sound that’s fuller and richer than either a dynamic or a condenser would produce.
The ribbon microphone consists of a very thin strip of conductor, such as aluminum (similar to tin foil) which is suspended between two magnetic rails. As the sound causes the ribbon to vibrate, an electric charge is produced which matches the vibrations. This electric charge is sent directly to the output of the microphone, and is amplified by the preamp.
Some ribbon microphones will be destroyed if phantom power is applied to them, because the current will go through the ribbon and burn it out. And some, such as iSK ribbon microphones have built in protection from this.
Ribbon microphones are inherently a figure 8 polar pickup pattern, because sound coming at the ribbon from 90 degrees simply won’t vibrate the ribbon element very much, or at all.