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"
 
 
*
Shure Broadcast Application Selection Guide 
*
Audio Technica Product Guide 
 
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
 
* News & reality: mic can be seen w/o disturbing the content 
* Narrative: mic cannot be seen 
 
 
ELECTRONICS
Link to AT site
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
 
Link to AT site
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
* low impedance mics and cable 
* XLR plugs 
* wired connections with shielded cables usually eliminate interference best 
Wireless: field/studio
* transmitter and receiver unit required 
 
* mic  connected to a transmitter "belt pack" worn by talent
* receiver connected to camcorder's audio jacks