Best microphones pick-up sound waves and convert those waves into an electric signal for use by audio equipment in one of two ways.
A dynamic (or moving coil) microphone operates by using a wire coil and a magnet to create the audio signal. The interaction of the wire coil and magnet is called electromagnetic induction and is mainly responsible for generating an output signal voltage. A diaphragm is attached to the coil, and it is mounted within the mic to ensure that it can move in reaction to a sound wave. If the diaphragm vibrates, the attached coil moves backwards and forwards within the magnetic field. This motion in the field generates an electric current (induction), which can be converted by audio equipment into sound waves. The effectiveness of the electrical current is directly linked to the motion from the coil.
Dynamic mics are excellent general-purpose microphones. They have got less moving parts than condenser mics, and for that reason they’re typically more rugged and durable. Furthermore, since they generate their own current, no external power source is required.
The physics behind the moving coil can play a role in limitations in frequency response. In most cases, dynamic microphones are less sensitive than condenser mics.
In a condenser microphone a voltage charge is applied towards the diaphragm by either battery power or phantom power. The diaphragm is mounted very close to a stationary back plate. Sound waves striking the diaphragm causes it to go closer and farther away from the back plate which in turn causes electrical charge fluctuations to take place. The interaction in between the diaphragm and back plate creates an electric component known as a capacitor (or condenser), and the resulting variations in voltage can be reinterpreted as sound waves from the receiving audio equipment.
Condenser microphones are very responsive and create a much stronger signal than dynamic mics. This makes them an excellent selection for professional settings including studio work, where it’s important to pick up vocal subtleties.
Typically Vocal Microphones acquire more moving parts than their dynamic counterparts and they are less durable. Also, given that they do not generate their very own current they need another power supply. (Battery or phantom power)
Precisely what is phantom power? Phantom power is actually a direct current (typically between 12 and 48 volts) that supplies microphones with power through audio cables. 48 volt phantom power is the most common and it is often tihdsy by microphone preamps and audio mixers.
The pickup pattern is most likely just about the most important factors in choosing a mic. The pattern determines which directions will and won’t get sounds. Pickup patterns for vocal microphones typically fall into the subsequent categories: omnidirectional, unidirectional and bidirectional.
Omnidirectional mics pick up sounds from all directions equally while a unidirectional mic is designed to only pick-up sound in one direction. Bidirectional mics are rarer, and are designed to pick-up from two sides – great for a two person podcast when sharing one particular mic. “Cardioid” is an additional term often used when describing the pickup patterns of microphones. A cardioid mic picks up sounds from your front, but there is some limited pickup through the sides. This can help to offer some tolerance for sideways movement in the speaker while recording.
Accessibility of power is yet another consideration for podcasting microphones. Most studio vocal microphones (condenser type) require phantom power – which means external power has to be presented to the equipment. This is frequently accomplished through mixers and mic preamps. USB microphones on the other hand, are able to connect right to a pc without requiring an outside source of energy. Dynamic mics are typically less sensitive but tend not to demand a source of energy.