Deck 5: Audio Signal-Processing, Amplification, and Reproduction Equipment and National Electrical Code Article 640

Question 1

What type of speaker cone is typically less than 2" in diameter and more often resemble a flat diaphragm rather than a cone?

A) Woofer
B) Mid-range
C) Horn
D) Tweeter

Answer 1

D

Question 2

A subwoofer should be pointed directly at the subject to hear the low frequency audio clearly.

Answer 2

False

Question 3

If a sound source were moved against a wall and the sphere of radiation were bisected, the measured sound pressure level would double.

Answer 3

True

Question 4

According to the National Electrical Code, audio circuit wiring can be placed directly on suspended ceiling tiles.

Question 5

What type of audio device is used to separate and direct a complex mixture of audio frequencies to their required sized loads?

A) A Crossover
B) A Filter
C) A Mixer
D) A Microphone

Question 6

An external power source for condenser microphones is called ________.

A) A Battery
B) A generator
C) Phantom Power
D) A Mixer

Question 7

What audio device converts an electrical current back into a mechanical vibration to reproduce sound?

A) A Loudspeaker
B) A Microphone
C) An Amplifier
D) All of the above

Question 8

When wiring audio equipment using metal racks, what are the requirements for grounding?

A) Both the metal rack and the equipment must be grounded
B) Only the metal rack needs to be grounded
C) Only the equipment needs to be grounded
D) Neither need to be grounded because an overcurrent protection device is required by the NEC

Question 9

The purpose of using bells or tones in a PA system is _______.

A) To assure that the telephone system is tied into the main audio circuit
B) To use them as the alert for the fire alarm system
C) To help get the attention of the audience before a message is conveyed
D) To be able to play music for the entire building

Question 10

The internal source resistance of a microphone and the capacitance of the microphone cable form what type of filter network at the input of the amplifier?

A) High-pass filter
B) Low-pass filter
C) Bandpass filter
D) Notch filter

Question 11

A balanced line is one that uses two circuit conductors having equal impedance from either side to ground.

Question 12

The power amplifier is the last stage of amplification between the signal input and the output speakers.

Question 13

An audio signal that has priority over all other signals is said to have precedence.

Question 14

A condenser microphone requires the use of an external power source to operate.

Question 15

According to the National Electrical Code, how far must audio equipment supplied by a branch-circuit be installed from the inside wall of the body of water?

A) Not less than 12 inches
B) 3ft.
C) 5ft.
D) 8ft.

Question 16

What piece of test equipment is designed to measure the frequency response of a room?

A) An oscilloscope
B) A sound level meter
C) An audio generator
D) A spectrum analyzer

Question 17

According to the National Electrical Code, audio circuits do not have any conduit fill restrictions.

Question 18

Wireless microphones operate using infrared technology between the amplifier and the microphone.

Question 19

External, wall-mount volume controls are made from adjustable audiotransformers.

Question 20

Balanced, low-impedance microphones will most likely use a/an __________ connector?

A) RCA
B) XLR
C) Monoplug
D) RJ-45

Question 27

A 70V audiotransformer tapped at 10W will output _________ voltage at the 8 Ω load. (assume the transformer has no loss).

Question 28

Calculate the amplifier power requirements when a load consists of ten 1W transformers, five 5W transformers and three 10W transformers.

Question 30

Calculate the decibel level of a 400µV microphone signal. (Assume a 1mW reference and 150 Ω impedance).