MUS 113 - Microphones and Vocabulary

Transducer

Generic name for a device which
transforms acoustic energy (sound) into
electrical energy (the audio signal)

Frequency Response Chart

Measure of mic output over the audible frequency range

Sensitivity

The measure of what the microphones signal output will be at a given SPL and frequency

Proximity Effect

A dramatic increase in low end sensitivity when the sound source is very close

Phantom Power

External power of 48 volts used on some microphones that's supplied from the mic preamp and travel through the cable.

Pad

Attenuates (lowers) the signal going down the cable by a fixed amount; Usually -10dB to prevent clipping.

HPF (High Pass Filter)

Allows high frequencies to pass and lowers the low frequencies.

Polar (Pickup) Pattern

Axis where mics pick up sound.

Omnidirectional

Picks up sound in all directions

Bidirectional (Figure 8)

Captures sound from the front and back.

Cardiod

Heart-shaped pickup pattern of a unidirectional microphone.

Hypercardioid

Very narrow unidirectional pickup pattern with a long reach. The mic is also sensitive to sounds coming directly from the back.

Carbon Microphone

A diaphragm is connected to a metallic "button" (brass) which sits like a lid on a "cup" of crushed carbon particles.

Dynamic Microphone

A moving coil around a moveable diaphragm.
1. Rugged
2. Resistant to moisture
3. Handles High SPL
4. Inexpensive
5. Usually Cardioid
6. Colored sound
7. Ignores Phantom Power

Condenser Microphone

A metal coated (gold) diaphragm (a few microns thick) is mounted above a conductive back plate. The signal generated has virtually no power and is of extremely high impedance.
1. Very sensitive
2. Extended frequency response
3. Flat leaning towards bright reproduction
4. Can be single pattern or multi-pattern
5. Requires phantom power
6. The smaller the diaphragm, the more sensitive

Electret Condenser

The diaphragm is made of a special plastic which only needs to be charged once. No phantom power needed

Ribbon Microphone

Thin corrugated metal placed between a magnetic diaphragm.
1. Rounded off highs)
2. Lower Output
3. Usually Bidirectional
4. Susceptible to damage
1. Wind
2. High SPL
5. Don't use Phantom Power
6. Smooth Midrange
7. Good compliment to digital

Pressure Zone Microphone (PZM)

The microphone element is placed extremely close and facing a flat plate. The mic responds to air pressure changes in the tiny gap between element and plate
½ omnidirectional

Pop Filter

Reduce the impact of wind (or vocal plosives)

Shock mount

Decouple the mic from mechanically transmitted energy (stage coupling)

DI Box

Converts unbalanced signal to balanced, from line/instrument to a mic.