Technical information

Jack plug, jack or TRS connector. Familiar from the larger type of headphone
jacks (or plugs), these are widely used in professional audio as well. There are
three common sizes, 6.4mm, 3.5mm and 2.5mm. They come in both mono (two
conductors) and stereo (three conductors) versions. The latter type at 6.4mm
size are often wired for balanced mono operation in pro-audio applications where
XLR plugs/sockets are not appropriate.
Jitter The phenomenon of a drift in the digital audio data delivered so that it does
not precisely match the sampling frequency, causing confusion in the receiving
equipment as to the appropriate value of the sample. A host of audible problems
with CDs and other digital formats have been laid at the feet of jitter. There is no
doubt that very precise master and upsampling clocks can help to make CD
players sound better.
kB Kilobyte. A measure of memory storage, a kilobyte equals 1,024 (i.e. 2
10
)
bytes.
kb/s or kbps -- Kilobits per second. A measure of the data flow rate for digital
audio from a DVD. Stands for thousands of bits per second. Generally, the
higher the number the better the quality.
kHz Kilohertz. A measure of frequency: 1,000 hertz.
L
LCD Liquid Crystal Display. Screen type, increasingly being used for large direct
view panel displays as well as touch screens for home A/V use.
LFE Low Frequency Effects channel, sometimes imprecisely known as the
subwoofer channel. This carries audio information covering frequencies up to 120
hertz and is designed to provide a substantial foundation to the bomb blasts,
rumbling trucks and the like in movies.
Linearity In any home entertainment system, at each stage the input and output
signals should be precisely proportional to each other (except where specifically
provided such as RIAA equalization or Dolby noise reduction). Thus if a
momentary 0.5 volts is fed to the input of an amplifier and it produced a three volt
output at its speaker terminals, then a momentary 1.0 volt input should produce a
six volt output. Any other output means that there is a non-linearity which will
manifest itself as harmonic distortion. Another example relates to digital to
analogue converters. Each particular quantization level in a PCM digital signal has
a precise analogue voltage level associated with it. Any variation means distortion.