Sound Reinforcement (V1 Appendix D)

Question 1

Electricity

Answer 1

Flow of electrons through a circuit

Question 2

Voltage and Volts

Answer 2

Measure of electric potential, Volt is the unit. It measures the pressure required to send one ampere of current through a resistance of one Ohm.

Question 3

Current and Amperes

Answer 3

Measurement of how many electrons pass through a reference point each second. Ampere is unit of measurement

Question 4

Resistance, Ohms, and Impedance

Answer 4

Resistance determines the limit for current, Ohm is measurement for resistance. Impedance is measurement of resistance along with other factors

Question 5

Ground

Answer 5

Electrical reference for voltage measurements. Earth ground is electrical potential of the earth as a reference, signal ground is signal potential of a specific piece of equipment.

Question 6

Decibel

Answer 6

Unit for intensity of sound. 0 dB is the lower limit of human hearing, 130 dB is the threshold of pain.

Question 7

Standard Operating Levels

Answer 7

Mic Level is no signal- -20dBu. Line Level (mixing console, processing equipment, and electronic keyboards is -20 - +30, speaker is above +30 (power amplifiers)

Question 8

Gain

Answer 8

Increase in amplitude of a signal

Question 9

Attenuation

Answer 9

Reduction in amplitude of a signal

Question 10

EMI

Answer 10

Electromagnetic Interference, sources can include TV, Radio, Cell phones, weather, power lines, lighting, power tools, medical equipment, mass transit systems, and other sound equipment. Also known as RFI (radio frequency interference)

Question 11

DI Boxes

Answer 11

Direct Injection Box, convert unbalanced high impedance signals to balance low impedance microphone level signal

Question 12

Ethernet Cable

Answer 12

Cable used to send information at high speeds between electronic devices, such as computers, routers, and IP (internet protocol) networks, and is referred to as a cat 5 or cat 6 cable.

Question 13

Multi-Channel Audio Snake

Answer 13

A single cable with houses several discrete dual conductor shielded audio cables. Can consist of several elements housed in one element, or breakouts going into a junction box.

Question 14

XLR Connectors

Answer 14

Three-pin XLR connectors are most commonly used when connecting microphones to mixing board, as well as various outputs to powered speakers. Used with dual conductor cables that help create balanced signals.

Question 15

Tip-Ring-Sleeve/Tip-Sleeve

Answer 15

TS uses a single conductor shielded cable, used for unbalanced connections, and have one insulator ring to separate sleeve and tip.

TRS look similar but have an extra conductor on the shaft just above the ground. TRS use dual-shielded cables and create balanced connections, and can run L/R mono signals for stereo output.

Question 16

Neutral Speakon/Powercon connectors

Answer 16

Neutral Speakon: Bridges connection between amplifiers and loudspeakers. Handle higher current than TS, TRS, or XLR and feature a safety locking mechanism.

Neutrik Powercon: Used as AC power connectors. Three-pole connector for neutral, line, and premating safety grounds. Also have locking mechanism.

Question 17

IEC connectors

Answer 17

Common power supply couplers with a number of different applications and configurations. Meet IEC (International Electrotechnical Commission) standards and are classified from C1-C24. Most common is C13 (female) and C14 (male) for audio and computer equipment. These are rated up to 250V AC.

Question 18

RJ45 Connectors

Answer 18

Registered Jack are a standard connector for network and telecommunication connections. They have 8 pin configuration and are similar to RJ11 (telephone jack).

Question 19

Neutrik Ethercon Connectors

Answer 19

Essentially an RJ45 connector specially designed for audio, video, and lighting applications.

Question 20

Dynamic Microphone

Answer 20

Most commonly used for live sound, largely because they are more economical and rugged. They have a voice coil/magnet assembly that works in conjunction with a small plastic diaphragm which vibrates in response to sound waves. The vibration within magnetic field is translated to electrical signal.

Question 21

Condenser Microphone

Answer 21

Can be more costly and more sensitive to temperature and humidity. Live sound is possible but not as common. But, they deliver much clearer and natural sound, especially within higher-frequencies.

They have an electronically charged diaphragm/back plate that forms a sound-sensitive capacitor. Sound waves vibrate a thin metal diaphragm, which is mounted in front of a fixed metal back plate. Electrical charge is created between the two, and signal is generated based on the spacing between the two.