7
About Rear Center Surround Channel Technology
The current standard for digital home theaters is based on 5.1 encoding and decoding. “5.1”
means that there are six channels that are recorded and reproduced discretely, or independent
from one another. “5” refers to the five channels whose speakers reproduce a wide frequency
range: left front, center front, right front, left surround, and right surround, while “.1” refers
to a sixth bass-only channel for the subwoofer.
Dolby® Laboratories recently developed a process for recording engineers to mix an
additional wide-range channel that is used to reproduce rear center surround (CS) effects.
This has come to be known as “6.1” or “Surround-EX.” Dolby Surround EX™ and DTS-
ES® Matrix are techniques used to encode a rear center surround channel into the LS and
RS channels of a 5.1 digital recording. THX Surround EX™ is Lucasfilm’s name for licensing
Dolby Surround EX when it is used in consumer products.
Dolby Surround EX specifications include two rear surround speakers to improve sound
distribution across the back of movie theaters (or a very wide home theater room). Some
companies call their systems “7.1” when there are two rear surround speakers, but their
source is still a single rear center surround channel. Dolby Surround EX encoding and THX
Surround EX decoding are both based on Dolby Pro Logic technology that was developed
in the 1980s.
To create a rear center surround channel, Parasound has chosen a newer and more sophisticated
matrix decoding technology called Circle Surround®. Compared to Dolby Surround EX,
Circle Surround provides superior reproduction of center surround effects with “6.1”-encoded
movies as well as deriving more effective rear center surround effects from normal 5.1-
encoded sources.
The Parasound CSE 6.1 reproduces its rear center surround channel from any sound track or
music encoded for Surround EX or DTS-ES Matrix. It offers two identical center surround
outputs, so you may use one or two CS channel amplifier channels and speakers to suit your
home theater’s size and room acoustics.
The CSE 6.1 has a unique “6.1 Info” indication LED. This LED illuminates when the CSE
6.1 recognizes potential rear center surround channel information present in the left and
right surround channels. Because the CSE 6.1 doesn’t require a 6.1-encoded digital bitstream
to derive a rear center surround channel, it can enhance surround effects in many digital 5.1
channel sources and even many two channel digital or analog sources recorded in Pro Logic
or simply rich with ambient spatial information.
The CSE 6.1 also includes a rear subwoofer output with its own switchable low-pass crossover.
Over the top? We don’t think so. When sound comes from behind you, it simply can’t
“connect” it to the low frequency sound emanating from a subwoofer that is located in front
of you. A special effects explosion or airplane fly-over coming from behind you sounds
much more convincing when its bass frequencies come from the same plane as the rear
speakers. A rear sub preserves the timbre and coherence of front-to-rear panned effects.