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M
M4A
The audio file format used by Apple in their
iTunes Music Store often appears on your
system with the ‘.m4a’ filename extension. M4A
can produce better audio quality than MP3
using less physical space for the files.
MHz (Mega Hertz)
One million cycles per second.
Mono (monaural)
The operation of an amplifier in one channel
for both input and output. Can refer to an
amplifier with only one channel of amplification
or operating in bridged mode. For low-
frequency amplification applications, it provides
better phase coherence and less distortion than
stereo operation.
MP3
A file format with a sound data compression
system. MP3 is the abbreviation of Motion
Picture Experts Group 1 (or MPEG-1) Audio
Layer 3. With the MP3 format, one CD-R or
CD-RW can contain about 10 times more data
than a regular CD.
Mute
A control found on receivers, and some mixers
or signal processing units that silences (mutes) a
signal path, or output.
O
Ohm
Measure of resistance to current (impedance).
The lower the impedance of a speaker, the
harder it is to drive.
P
PCM (Pulse Code Modulation)
Pioneering form of digital recording.
I
Impedance
The resistance to the flow of an electric current
in a circuit. This is effectively the electrical load
that a loudspeaker presents to the amplifier
which drives it and is measured in ohms.
Input sensitivity
SPL (sound pressure level) a speaker produces,
given one watt of power, measured from a
one-meter distance at a typical input frequency
(usually 1kHz unless otherwise noted on the
speaker).
Interface
A device or protocol which facilitates the linking
of any two devices or systems; or when used as
a verb (‘to interface’), the process of linking.
IP address
An IP (Internet Protocol) address is a unique
computer address that enables electronic
devices to communicate with and identify each
other.
K
Kbps
Kilobits per second. A digital-data-rate
measurement system which is often used with
highly compressed formats such as AAC, DAB,
MP3 etc. The higher the amount, the better the
quality generally is.
Kilo Hertz (kHz)
1000Hz or 1000 cycles per second.
L
LCD (Liquid Crystal Display)
Probably the most common way to show
visual information on non-computer electronic
equipment.
Lossless compression
A system for reducing the number of data bits
(density) in a musical signal without corrupting
the original.
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