Test 2 Flashcards
Capacitance Mic Features
Most sensitive, requires power supply, very common, most expensive
Moving Coil Mic Features
most reliable, low noise, low distortion, inexpensive
-rugged
Ribbon Mic Features
Most fragile, easy to distort, least common, more sensitive than moving coil mic
What is a microphone?
electro-acoustic device that converts acoustical energy into electrical energy (transducer)
Capacitance mic first developed:
in 1916 by E.C. Wente
Build of capacitance mic
two thin plates (one moveable/one fixed) w/ charge applied
Moving coil mic first developed:
in 1928 by E.C. Wente
Build of moving coil mic
small diaphragm and voice coil moving in magnetic field. Sound waves cause diaphragm o move in the magnetic field, generating a voltage proportional to sound pressure
Ribbon mic first developed:
introduced by RCA in 1932 designed by Harry Olsen
Build of Ribbon mic
thin ribbon suspended in magnetic field. Sound pressure between front & back cause it to move w/ current flow proportional to acoustic waveform
(moving coil, ribbon) *All dynamic mics contain:
magnets
Polar Pattern:
graph of sensitivity w/ respect to direction and frequency
omnidirectional
picks up sound equally in all directions
bi-directional
picks up sound equally from two opposite directions
uni-directional
picks up sound primarily in one direction
Multi-Directional microphone
miss that are capable of switching from one pick-up pattern to another
Sound a mic receives is dependent on 3 external variables:
1) The nature of the sound source
2) The acoustic environment
3) *The placement of the mic
Close micing
(< 3ft from source) aids sound isolation, minimizes acoustics, little phase cancellation
Distant micing
(> 3ft from source) natural blend in acoustical space, room tone of ambience, high probability of phase cancellation
Mic placing technique 3:1 rule
- each mic at least 3x farther apart than each is from its source
- reduces phase cancellation
Stereo micing
- 2 identical mics
- 3-30ft apart
Coincident (X/Y)
- 2 identical mics
- capsules aligned; angle of 90-135 degrees
mid-side
- 2 complimentary mics
- 1 directional; 1 bi-directional
(Mic Characteristics) Transient response:
how quickly a mics diaphragm will react to acoustic wave
