Glossary
Active:
Uses electrical power.
Amplifier:
An electronic device that increases the cur-
rent of a signal, providing power to the loudspeakers (i.e.
power amplifier, integrated amplifier, receiver).
Bass:
The range of audio frequencies below 160Hz,
characterized by low pitch.
Crossover:
An electronic circuit that divides an audio
signal into different frequency ranges.
Distortion:
Any deviation from the original signal,
caused by any type of equipment.
Driver:
The moving part of a loudspeaker which radiates
energy.
Dynamics:
Variations in loudness of sound.
Efficiency:
See sensitivity.
Frequency:
A rate of vibration which corresponds to
musical pitch in the audio band, expressed in Hertz (Hz).
Full Range:
A signal encompassing the entire frequen-
cy spectrum, not filtered above or below
a certain frequency.
Hertz (Hz):
A unit of frequency equal to one cycle per
second, used to measure the frequency of a signal or
sound.
High-Pass Filter:
A filter that passes only frequencies
above a certain lower limit; electronically removes low
frequencies from a full range signal.
Impedance:
A measure of the total opposition to current
flow in an alternating current circuit, described in ohms.
In Phase:
The polarity of an audio signal when connect-
ed as follows: (+) to (+) and (-) to (-).
Integrated Amplifier:
Has preamplifier and amplifier
built into one chassis.
Interconnect Cable:
A length of shielded wire with plugs
at both ends for feeding signals from
one electronic device to another.
LFE:
Low Frequency Effects; an RCA output for connec-
tion to a subwoofer.
Line-Level Connection:
Low level RCA/phono type
connection.
Load:
A term used to describe the impedance which a
speaker presents to an amplifier.
Low-Pass Filter:
A filter that passes only frequencies
below a certain upper limit; electronically removes high
frequencies from a full range signal.
Main Speakers:
Front L & R channel speakers, some-
times referred to as satellites.
Main-in:
A line-level RCA input on the back of a receiv-
er, integrated amplifier or power amplifier.
Midrange:
The frequency span of the middle of the
audio range, roughly 160Hz - 3OOOHz. Also used to
describe the driver which reproduces these frequencies.
Ohm:
A unit of electrical resistance; that which opposes
an electric current in a conductor. In audio, a measure
of the load presented by a device to an electrical source.
Out-of-Phase:
The polarity of an audio signal when con-
nected as follows: (+) to (-) and (-) to (+).
Passive:
Uses no electrical power.
Phase:
An expression of the relative polarities of two
identical signals.
Power Handling:
The ability of a loudspeaker to operate
without distortion when given varying amounts of
wattage.
Preamplifier:
An electronic device that selects sources
and passes line-level signal to amplifier.
Pre-Out:
A line-level RCA output on the back of a receiv-
er, integrated amplifier or preamplifier.
Receiver:
Has preamplifier, amplifier and tuner built into
one chassis.
Satellite:
Front L & R speakers when used with a sub-
woofer. Referred to as main speakers.
Sensitivity (same as efficiency):
A measure of how
much of the input electrical energy is converted into
sound energy, measured in decibels.
Signal:
The series of continually changing electrical volt-
ages that correspond to variations in the loudness of the
original sound.
Speaker-Level Connection:
The connection between a
loudspeaker and an amplifier.
Subwoofer:
A driver designed to operate over the low
bass portion of the audio range. Also refers to a system
consisting of a woofer and its enclosure which are phys-
ically separate from the upper range loudspeakers.
Surround Speakers:
Speakers located in the side or
rear for surround channel effects.
Treble:
The upper part of the frequency spectrum, con-
sisting of frequencies above about 1300Hz.
Tweeter:
A small driver designed to reproduce high fre-
quencies.
Watt:
A measure of electrical power, combining the volt-
age with the electrical current required to drive the loud-
speaker.
Weight:
Low frequencies below 50Hz.
Woofer:
A driver designed to operate over the bass-
portion of the audio range.
