Dynamic Microphones

A microphone is a device used to amplify audio from an audible source, meaning a device that transmits its sound through the air. They have a number of uses, but the primary ones that most situations call for are in live venues or recorded scenarios. Either way, a microphone has a frequent presence in the world of audio.

How are dynamic microphones used for live and recorded sessions?

For live situations:

  • Allowing speakers or singers to be heard through public address systems - The vocal speech or singing of the mic user can be heard in large venues. Dynamic microphones are often used in these situations.
  • Allowing a musical instrument to be selectively amplified in order for it to be heard in clearer context with other instruments or vocals - Dynamic or condenser microphones might be used for these situations, depending upon the venue and other factors.

For recorded situations:

  • Recording of vocal speech or singing - A more fragile, but sensitive condenser microphone will often, but not always, be preferred for this scenario. Certain singers, such as Michael Jackson or Bono, have recorded hit records using dynamic mics like the Shure SM7 or Shure SM58.
  • Recording of musical instruments - The sound pressure levels of the source will dictate the type of microphone to be used. A snare drum or a guitar amplifier, either of which can be quite loud, will more often be recorded with a dynamic, whereas a violin or flute might warrant condenser microphones.
  • Film and video recording - In this scenario, the entire audio spectrum: speech, footsteps, background noise, etc., may all be desired by the project at hand. A range of special condenser microphones by brands like Sennheiser and AKG designed for these purposes would be utilized.
How does a dynamic microphone work?

Microphones have a diaphragm, which captures the vibrations from the source and converts them into an electric signal. This signal can then be transmitted to an amplifier to be reconverted to sound. The sound can be electronically increased in volume.

A dynamic microphone has a diaphragm that is passive, meaning that it requires no external power source, and can generate its electric signal by pure physics. As a result, it is sturdier and can be subjected to more handling. It usually has a cardioid, or heart-shaped pickup pattern for better noise rejection.

Do you need phantom power for a dynamic mic?

Phantom power is a 48-volt external power supply that is used by ribbon, condenser, and tube microphones in order to operate. As dynamics are passive, external power is not necessary. In multiple mic setups that combine powered and passive mics, sending 48 volts to a passive mic will not affect it.

Is Shure SM57 a dynamic microphone?

The Shure SM57 and Sennheiser 421 are two examples of dynamic microphones and can be used for drums, electric guitars, and all types of sound sources. A Shure dynamic cardioid microphone like the SM57 has been used by the President of the United States for all public speaking events since the 1970s.