Mics: The Sonic Lens

Recording Chain

• A system or “ecosystem” for recording and playback

3 Main Considerations for Mic Choice

• 1) Transduction: how a mic turns sound to audio

• 2) Polar pattern: the directivity of a mic or the direction at which it picks up sound

• 3) Type: the shape of the body of the mic

Transduction

• Transduction w/ mic= turning sound to audio; vibrations to electricity

– Speaker is a transducer, but works in opposite way

• 2 main mic types:

– 1) dynamic

– 2) condenser

– 3) also ribbon (for string instruments; super sensitive, figure 8 polar pattern...don't worry about these)

Dynamic

• Do not require external power

• Rugged: drums, explosions

• Can handle loud noises with less distortion

• Does not pick up sound, esp. high frequencies as accurately because diaphragm moves slowly

• Great for beginning recordists, news reporting, etc.

Condenser

• Always require phantom power (+48 volts or some rarely want +24v/+12v)

• More “faithful” sound reproduction

• Cannot handle loud sounds for a long time

• Most used in sfx, Foley, broadcast/reality TV/film production recording (of mainly dialog), and studio

Phantom Power

• All condenser mics require power

• Some you can put a battery in (i.e. NTG-2)

• Many you cannot, thus they require Phantom Power, usually +48v

• This uses the power on your camcorder, audio recorder, or mixing board and will use such a device's battery

Polar Patterns

• Pickup pattern

• How a capsule (the sensitive transducer part of mic) “sees” sound from the front of a microphone

Omnidirectional

• Picks up sound at 360 degrees equally

– Except high frequencies (short wavelengths)

• Have nice natural sound

• Good for recording atmos (if a room/atmos has a nice tone)

• Least susceptible to wind induced noise

• Can also be good for the voice if you want natural reverb

Cardiod

• Unidirectional, heart-shaped pattern

• Rejects some sound on sides / back of mic

• Susceptible to wind-induced noise

• Point at sound source

• Used for dialog, sfx, and specific sounds to add to atmos (good for most applications)

Hypercardiod

• Unidirectional

• Some sensitivity in the back of the mic

• Susceptible to wind-induced noise

• Mostly used in sfx, music, and Foley

Supercardiod

• Rejects most side sound and ALL on the back of mic (Rode NTG-2)

• Unidirectional

• Use when sound source is far from mic or lots of ambient noise

• Susceptible to wind-induced noise

• Mostly used in tv/film dialog, but fine for sfx/Foley

Shotgun

• Aka “boom” mic

• Focus on sound in front of mic

• Pulls sound closer like zoom lens

• Best mic dialog on TV/film captured with this, SFX that you have to capture from a long distance (i.e. bird sound in a tree)

Spaced Pair Stereo

• 3:1 rule (place the mics 3 times as far from each other as they are from the sound source).

XY Stereo Recording

Type

• Shotgun

• Handheld

• Lav

• Binaural

Accessories

• Air diffusion

• Vibration dampening

• Why?

Cables and Connectors

• Balanced vs. Unbalanced

• Unbalanced: more susceptible to hum

– Most consumer audio: RCA, 1/4”, 1/8”

– Work at short distance

Cables and Connectors Cont’d

• Balanced: rejects hum, AC and RFI noise and other low frequency interference

– Can only use phantom power (+48v)

– ALWAYS use in professional audio production

– Can work at long and short distances

– Avoid using unbalanced outputs w/ balanced inputs

– 1/4” and 1/8”, but must be TRS to be balanced

Line Level vs. Mic Level

• Line Level=a higher level signal

– Line input for: audio mixer, iPod, computer, CD player, etc.

• Mic Level=lower level signal

– Mic input: has a mic preamplifier to boost the signal (some mics also require +48v)

– If you plug a line device into the mic input will get a loud, distorted signal

Other Factors

• SPL= sound pressure level

• Frequency response: range of frequency a mic can reproduce accurately

• Flat frequency: preferred as it doesn't “color” sound. You “equalize” this in post.

– Look for a mic that is 20Hz-20KHz for flat frequency

Other Factors Cont’d

• If hiding a mic under actors' clothing, find a mic that responds/emphasizes high frequencies. Why?

• HPF: high pass aka low cut filter. Reduces low frequencies (i.e. AC/fridge/traffic rumble.)

– Don't use usually

Proximity Effect

• When mic is too close to sound source

• Increases low frequencies

• Make voice, sound, instrument sound more bassy or booming

• Move mic away a bit to correct this