MUS221: Microphones (Week 6)

A good recording starts with

• The sound of the room

• The character and condition of the instrument

• The capabilities and preparation of the performer

microphone

• a transducer that converts acoustic energy into electrical energy

• the first piece of equipment in the signal chain for capturing acoustic sounds

• an only reproduce what they are given!

diaphragm

• vibrates in response to sound waves

  • This movement is converted into an electrical signal

preamplifier

boosts the relatively weak electrical signal from a microphone

• usually built into audio interfaces and mixers, though standalone boutique options exist

• Dynamic Microphones

• the diaphragm is attached to a voice coil that moves within a magnetic field, generating an equivalent electrical signal

• The simplicity of this mechanism makes dynamic mics rugged and affordable but with some limitations in reproducing very low and high frequencies

• Condenser Microphones

• In condenser microphones, the diaphragm moves in relation to an electrically charged plate

• This requires phantom power for operation

  • 48v

• This mechanism is a little more fragile than dynamic mics but is also more sensitive with improved low and high frequency reproduction

• Choosing a Microphone

• Where will the microphone be used?

  • Live vs. studio, large vs. small room, ect.

• What instruments are being recorded?

• What tonal characteristics are desired?

polar pattern

• describes the directional sensitivity of a microphone

  • How well it picks up sound from different directions

• Cardioid (unidirectional)

• Figure 8 (bidirectional)

• Omnidirectional

most common polar patterns.

frequency response

• a microphone’s sensitivity across a range of frequencies

• A flatter frequency response sounds more natural

• A tailored or shaped frequency response enhances certain characteristics of different instruments

• ambient room sound

A microphone placed further from the source will capture more

proximity effect

• enhancing low frequencies when very close to the source (“radio voice”)

Phase

•  the starting point of a waveform

• Microphones at different distances will receive sound waves at different parts of their phase, causing some cancellation