User Guide

170
Surround basics
when recording only to simulate it again later using
reverb effects.
A few definitions of terms
The following definitions are derived from the
recommendations of the International
Telecommunication Union (ITU). Each of these
technical writings is a recommendation geared
toward establishing technical standards without
undermining audio engineers’ creativity and
willingness to experiment.
3/2: Main recommendation for discrete multi-
channel stereophony with three front speakers (left/
center/right) and two rear channels (LS = left
surround and RS). Standard according to BS ITU-R
775.
5.1: A variation on the 3/2 recommendation that
extends the standard to include a frequency-limited
subsonic bass channel (low frequency effect, LFE).
Sweet spot: The best possible listening position.
The ITU recommends a specific speaker array for
every multi-channel audio type, the goal being to
achieve the largest possible listening area with the
highest possible fidelity. The array recommended for
the 5.1 format is depicted on page 171.
Audio shoptalk revealed: Surround, Dolby
Surround, Dolby Digital
Neuron supports surround format 5.1, a digital
multi-channel format with six discrete channels (see
definition).
The 5.1 format is not to be confused with the first
commercial multi-channel technology Dolby
Surround®. It is based on a matrix comprising two
analog transmission channels. A frequency limited
center channel and a frequency limited rear surround
channel are encoded into a two-channel stereo
signal. The rear channel is delayed and sent to two
speakers. The center channel is either distributed in
equal parts to the left and right front channel or
rendered via a dedicated center speaker (depending
on decoder).
The 5.1 multi-channel format provides the technical
underpinning for the encoding and transmission
format Dolby Digital® widely used for DVDs.
Dolby Surround®, Dolby Digital® and Virtual
Surround® (which is achieved by phase and frequency
shifting without requiring additional speakers) are
not multi-channel formats. They are the names of
CODECs (the proprietary coding/decoding algorithms
of Dolby Labs™) and as such do not necessarily refer
to the number of channels.
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