SOUND GATHERING: Part I
Technical Aspects of Microphones
Sound - changes in air pressure, compression and rarefication
Measured in . . .
FREQUENCY - cycles per second
AMPLITUDE - volume
MICROPHONES - changes air pressure into electrical signal, "transduction"
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3 WAYS OF CLASSIFYING MICROPHONES:
1. USE AND DESIGN
2. ELECTRONICS - method of converting sound waves to electrical energy
3. PICK-UP PATTERN
MICROPHONE DESIGN / USE CATEGORIES
1. Hand-held: field, news
(dynamic, omni/uni)
2. Studio: desk or boom mounted, warm,
full sound (ribbon)
3. Lavalier: clipped to lapel, low visibility
(condenser, omni)
4. Shotgun / Boom: highly directional pickup pattern, out of shot (super/hyper cardioid, condenser)
5. Headset: sports, technical crew
Additional Microphone Choice Considerations
Genre: news, sports, "reality" vs. narrative, film style
ELECTRONICS
1. Dynamic/Moving Coil
Coil moves inside magnetic field, generates signal.
Most handheld mics are Dynamic.
+ least expensive, durable
- narrow frequency response (less highs)
2. Ribbon
Thin ribbon b/t magnetic poles, generates signal.
+ warm & rich, high frequencies, sensitive
- delicate, prone to popping, $$
3. Condenser
Fixed back plate is charged, vibrations of diaphragm cause changes in charge.
A power source is required. Any mic w/a power source is considered a condenser mic.
Shotguns and lavs are most often condensers.
+ crisp, high bright, durable, flexible
- moisture sensitive, $$$, must have power supply
PICKUP PATTERN
direction of best reception of sound
1. OMNI DIRECTIONAL
- equal on all sides, apple/ball shaped pattern
2. BI-DIRECTIONAL
- front and rear pickup
3. CARDIOID (heart shaped) - Uni-directional (one-direction)
Ports in rear of mic cancel sound from rear.
SuperCardioid
Hyper cardioid
Additional technical consideration: wireless or wired connection.
Wired connection: studio/field
Wireless: field/studio