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18 Cards in this Set
- Front
- Back
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What is the definition of a microphone? |
A sound instrument that transducers, or converts sound pressure waves into voltage |
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What is the definition of a diaphragm? |
Thin circular piece of metal, plastic or paper that moves back and forth with the incoming sound waves |
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What is the definition of a transducer? |
Connected to the diaphragm, converts the mechanical motion into electromagnetic using a moving coil, ribbon, or electret (condenser) |
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What is a moving coil mic |
Simple construction used in dynamic microphones, a moving coil of wire attached to a diaphragm induces a voltage of about 1 millivolt |
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What is a ribbon mic |
Movement of a thin paper ribbon in between a magnetic field induces a very low voltage |
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What is an electrostatic (condenser) mic? |
The diaphragm and backplate of the transducer create a capacitor. A voltage is supplied to them. Movement of the diaphragm causes variances in the capacitance which causes changes in voltage. Q=CV. Qis the constant charge in coulombs. An amplifier is necessary close to the transducer because of the very high impedance that is susceptible to induced noise from power lines or other interference. |
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What is an electret mic? |
Have a permanent charge on either the diaphragm or the backplate. Removes the need for polarizing voltage across capsule, but still needs lower voltage supply for the pre amplifier |
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What is phantom power? |
48v standard for microphone powering. It is supplied through the two positive leeds in a balanced microphone cable with the negative coming through the cable ground wire |
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What are pickup patterns /or polar response? |
Allows for discrimination of specific sounds or frequencies in the recording process |
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What is an omni directional microphone? |
Responds well to sounds coming from all directions. Slight shadow in high frequencies from behind the mic, because of its physical shape. |
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What is a figure of eight microphone? |
Two touching spheres, front and behind, sounds from the sides are discriminated against |
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What is a cardiod microphone? |
Heart shaped pickup pattern with lowest response to sounds behind the capsule. Tunes in recording by 20 dB more to sounds in front of the capsule. Allows for noise or unwanted sound to be reduced in the recording. |
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What is a hypercardioid (shotgun) microphone? |
Very directional microphone used for outdoor news gathering or film work. Spits around the side cause sounds that come from behind the capsule to be out of phase and cancelled out. |
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What is a parabolic microphone? |
An omni directional microphone placed at the focal point of a parabolic dish. Extremely directional. |
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What is a pressure zone microphone (PZM) |
Omni directional microphone that uses the surface it is mounted to to act as the sound gathering source. The mic is mounted 1mm above the surface to eliminate phase. Used for room recordings, certain instruments, theatre. |
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What is the position of xy (American) microphone placement? |
90degree cardiod 1" apart |
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What is the N. O. S. (Dutch radio) microphone positioning? |
90degree cardioids 7" apart |
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What is the ORFT (French radio) microphone positioning? |
110degree cardioids, 9" apart |
