Microphones

Dynamic microphones

Do not require a power source, produces mic level signal

Condenser microphones

Pre amplifier needed, power supply may be external phantom or battery

More sensitive to higher frequencies and wider overall frequency response

Electret Microphones

Type of condenser mic, electret provides permanent power to 1 side of capacitor so small batteries or phantom power may be used

MEMS

Used in mics so sensitivity can be increased and on chip processing for amplifier and analog to digital conversion

Phantom power

Remote power, 12-48V DC

Balanced design

Omnidirectional

Cardiod

Pickup generally from one direction, rejected from side, and rejected most at rear

Hypercardiod

Rejects most sound from sides, more sound can be picked up at rear

Supercardiod

Better directionality, better rejection from sides and more rear pickup that hyper

Bidirectional

Pickup equal in opposite directions wth little to none at sides

Sensitivity

Defines a mics electrical output level given a reference sound input. More sensitive = more output

(Condensers more sensitive than dynamic)

Frequency Response

Defines electrical output level over audible frequency spectrum

Polar plots

Represent a mics directionality and frequency response characteristics

Maximum Voltage Transfer/Impedance

A device output impedance should be 1/10th or less than the impedance of the device it is being plugged into

Microphone Impedance

Range of 200 ohms or less for professional mics

Impedance

AC' Opposition to the flow of electrons in an audio signal

Resistance

Opposition of flow of electrons in a DC current

Mic level

only a few mv

Mic pre amp

To amplify the mic signal

Line level

Where all signal routing and processing occurs

1V, 600 ohms for professional audio

Line Level (consumer)

316mv, 10 ohm@ 1kHz - 3.5mm or RCA

Loudspeaker level

after amplfication, 4V?