Best microphones pick up sound waves and convert those waves into an electrical signal for use by audio equipment in one of two ways.
A dynamic (or moving coil) microphone operates using a wire coil along with a magnet to create the audio signal. The interaction from the wire coil and magnet is called electromagnetic induction and accounts for generating an output signal voltage. A diaphragm is attached to the coil, and is also mounted in the mic so that it can relocate reply to a sound wave. When the diaphragm vibrates, the attached coil moves backwards and forwards within the magnetic field. This motion inside the field generates an electric current (induction), which can be converted by audio equipment into sound waves. The strength of the electrical current is directly linked to the motion of the coil.
Dynamic mics are excellent general-purpose microphones. They may have less moving parts than condenser mics, and consequently they’re typically more rugged and durable. Additionally, since they generate their very own current, no external source of energy is required.
The physics behind the moving coil can contribute to limitations in frequency response. Most of the time, dynamic microphones are less sensitive than condenser mics.
In a condenser microphone a voltage charge is applied for the diaphragm by either a battery or phantom power. The diaphragm is mounted not far from a stationary back plate. Sound waves showing up in the diaphragm causes it to go closer and farther out of the back plate that causes electrical charge fluctuations to happen. The interaction involving the diaphragm and back plate creates an electrical component known as a capacitor (or condenser), and the resulting variations in voltage can be reinterpreted as sound waves by the receiving audio equipment.
Condenser microphones are extremely responsive and make a much stronger signal than dynamic mics. This makes them a perfect option for professional settings like studio work, where it’s important to get vocal subtleties.
Typically Condenser Microphones have more moving parts than their dynamic counterparts and are less durable. Also, given that they usually do not generate their particular current they need an outside power supply. (Battery or phantom power)
Precisely what is phantom power? Phantom power is really a direct current (typically between 12 and 48 volts) that supplies microphones with power through audio cables. 48 volt phantom power is regarded as the common and is also often tihdsy by microphone preamps and audio mixers.
The pickup pattern is probably probably the most important factors in choosing a mic. The pattern determines which directions will and won’t pick-up sounds. Pickup patterns for vocal microphones typically belong to the following categories: omnidirectional, unidirectional and bidirectional.
Omnidirectional mics pick up sounds from all of directions equally while a unidirectional mic is made to only get sound from one direction. Bidirectional mics are rarer, and are created to pick-up from two sides – great for a two person podcast when sharing just one mic. “Cardioid” is another term often used when describing the pickup patterns of microphones. A cardioid mic picks up sounds from the front, there is however some limited pickup from the sides. This helps to offer some tolerance for sideways movement of the speaker while recording.
Availability of power is yet another consideration for podcasting microphones. Most studio vocal microphones (condenser type) require phantom power – meaning external power has to be given to the equipment. This is most often accomplished by the use of mixers and mic preamps. USB microphones on the contrary, are able to connect straight to a pc without requiring another source of energy. Dynamic mics are typically less sensitive but tend not to demand a power source.