Technical information

SACD Super Audio CD. An audio format developed by Sony and Philips to take on
DVD Audio. Both formats are being superceeded by 20 and 24 bit music
downloads and bluray now.
Sample One from a series of digital measurements taken of an analogue signal at
regular intervals. The timing of the intervals is determined by the sampling
frequency. The accuracy of the sample is determined by the sample's bit depth
and the quality of the ADC.
Sampling frequency The number of digital samples taken each second of an
analogue audio signal. For the compact disc, this is always 44,100 samples per
second (usually expressed as hertz). For DVD it is typically 48,000 hertz, but may
be 96,000. The higher the figure, the more accurately the analogue source is
recorded, giving an extended high frequency response, and the more space the
signal requires.
Satellite speakers Small loudspeakers designed to deliver only midrange and high
frequency audio. They are intended to operate in conjunction with a subwoofer
which delivers the bass.
SBM Super Bit Mapped. An analogue to digital conversion system developed by
Sony that incorporates a form of noise shaping, designed to deliver very good
performance results in the middle frequencies, at the cost of a poor signal to
noise ratio in the high frequencies.
SCART Syndicat francais des Constructeurs d'Appareils Radio et Television. A
large connector, carrying 21 pins, designed to connect VCRs and DVDs to TVs.
Convenient but superceeded by much better cable alternatives offering higher
fidelity A/V.
Sensitivity A measure of the efficiency with which loudspeakers turn the electrical
energy provided by a power amplifier into acoustic energy. The more sensitive,
the greater the volume for a given amount of power. This is normally measured
as the sound pressure level in decibels (dBSPL) achieved by the loudspeaker in an
anechoic chamber at a distance of one metre with a 2.83 volt 1kHz signal applied
(2.83 volts is the voltage required to deliver one watt to an eight ohm load.)
Sensitivities generally range from not much more than 80dB up to 100dB. Each
3dB increase in sensitivity is equivalent to doubling the amount of power, so for a
loud system it is far better to choose sensitive loudspeakers rather than pay for a
higher-powered amplifier.
Separation A measure of the degree to which leakage from one channel of sound
to another channel (crosstalk) is limited. This is typically measured in decibels
(e.g. -90dB at 1kHz). While great emphasis is placed on this figure, the reality is