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Reference of Electronic Terms
AMPLIFIER: A device capable of increasing the magnitude or power level of a voltage or current that is varying with time (frequency), without
distorting the wave form of the signal. The amplifier Is, just as the word implies, a signal amplifier. The incoming signal from any program material
source is far too weak to power a speaker system. The role of the amplifier Is to take that weak signal and strengthen Ittothenecessary power level
to operate the loudspeakers with minimal distortion.
AMPERE: A unit of measurement of electrical current (I).
BALANCED CABLE: A pair of wires surrounded by a braided shield.
ATTENUATION: The reduction In level of a signal.
BALANCED LINE: A transmission line consisting of two conductors plus a braided shield, capable of being operated so that the voltages of the two
conductors are equal In magnitude (voltage) and opposite in polarity with respect to ground.
BANDWIDTH: Response characteristic in which a definite band of frequencies having a low frequency and high frequency limitare transmitted or
amplified uniformly.
BUS: A conductor that serves as a common connector to several signal sources, always associated with a mix amplifier.
CLIPPING: Amplifier overload causing a squaring off or undesirable change In the wave form resulting In distortion or perceptible mutilation of
audio signals.
COMPRESSION: Reduction of the effective gain of an amplifier at one level of signal with respect to the gain at a lower signal level.
CURRENT: (I) The rate of flow (measured In amperes) of electricity in a conductor or circuit.
CUT: A term used to indicate the reduction In gain of a frequency or band of frequencies when equalizing an audio signal.
dB: (Decibel) — A unit for describing the ratio of two voltages, currents, or powers. The decibel Is based on a logarithmic scale, when measuring
differences in sound pressure level (SPL), the amount of change in sound pressure level perceivable Is directly proportional to the amount of
stimulus (the more sound present, the greater the change must be, to be perceived).
dBM: A decibel scale referenced to 0 dBM = 1 milliwatt Into 600 ohms or .773 volts RMS.
dBV: A decibel scale referenced to 1 volt RMS; 0 dBV = 1 volt.
DIP: A reduction in gain at a certain frequency also called a notch.
ENCLOSURE: An acoustically designed housing or structure for a speaker.
FEEDBACK: (Electronic) The return of a portion of the output of a circuit to Its input. (Acoustic) The regeneration of a signal from the output of a
sound system into a microphone Input.
FILTER: An electrical or electronic device that permits certain frequencies to pass while obstructing others such as a crossover filter used with
loudspeakers.
FREQUENCY: The number of vibrations or osci l lations In units per second. Measured in cycles or hertz per seconds. The rate of repetition In cycles
per second (Hertz) of musical pitch as well as of electrical signals. For exam pie, the number of waves per second a vibrating device such as piano or
violin string moves back and forth In each second of time to produce a musical tone.
FULL RANGE: The entire audio spectrum, 20 Hz - 20 KHz.
GAIN: An Increase In strength or amplitude of a signal. The Increase in signal power that Is produced by an amplifier; usually given as the ratio of
output to input voltage, current, or power expressed In decibels.
HEADROOM: The difference between the average operating power level of an amplifier circuit and the point at which clipping or severe distortion
occurs.
HERTZ (Hz): A unit of measurement, previously referred to as cycles per second used to Indicate the frequency of sound or electrical wave. A unit of
motion referenced to a time period of one second. The frequency of a vibration or oscillation in units per second.
IMPEDANCE: The total opposition to alternating current flow presented by a circuit. The resistance to the flow of alternating current In an electrical
circuit, generally categorized as either "high" or "low", but always expressed in ohms. Commonly used to rate electrical Input and output
characteristics of components so that proper "match" can be made when interconnecting two or more devices, such as a microphone, loudspeaker
or amplifier.
JACK: A receptacle on a receiver, tape recorder, amplifier or other component Into which a mating connector can be plugged.
MASTER: Main level or gain control for a Bus or Mix.
OHM: The unit of electrical resistance, equal to the resistance through with a current of one ampere will flow when there Is a potential difference of
one volt across It. Ohm Is the unit of measure used to express opposition to current flow. Every wire or part through which electricity passes has
some resistance to that passage.
PARALLEL: An electric circuit in which the elements or components are connected between two points with one of the two ends of each
component connected to each point,
RESISTANCE: Opposition to the flow of electrical current.
RIAA: Stands for Recording Industry Association of America. A type of preamplifier used for turntables. It Is necessary to use an RIAA preamp when
using a magnetic cartridge.
RMS: (Root Means Square Value) The square root of the time average of the square of a quantity; for a periodic quantity the average is taken over
one complete cycle. RMS voltage is .707 times the peak voltage of a sine wave.
SPL: (Sound Pressure Level) The level or Intensity at a point In a sound field (loudness). The deviation above and below normal atmospheric
pressure.
0 dB: In the measurement of SPL or Sound Pressure Level, 0 dB is referenced to the threshold of hearing or auditory perception of a tone of 1000
cycles (hertz) per second (1 KHz).
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