SMART Devices
Center Surround 3X TM
3-Channel Surround Adapter
(CS-3X, Jr.)
PERRY SUN
The SMART Devices Center Surround 3X, or equivalently, the CS-3X, Jr., is a home theatre component designed specifically for extracting the back surround channel, in order to allow listeners to experience sounds behind them, as well as to obtain a more convincing perception of sounds circling around and over them. The CS-3X, Jr. is the home theatre version of the professional CS-3X adapter, used in movie theatres for Dolby Digital Surround EX, the format which encodes a back surround channel onto the existing left and right surround channels from 5. 1-channel digital film sound.
SMART has implemented the patented Circle Surround matrix in the CS-3X, Jr. The component was designed from the start to decode Dolby Digital Surround EX TM films, of course, but SMART advocates experimentation with films that aren't encoded. The advantage claimed for using Circle Surround TM, as opposed to the Dolby ProLogic' matrix, is that the latter has a tendency to collapse imaging to the center channel, whenever the encoded left and right channels are carrying the same signal. For films that are encoded for Dolby Digital Surround EX playback, this steering is intentional. However, for other films, such an effect may be undesirable, much less unpredictable. Circle Surround is designed to maintain wide channel separation, regardless of signal content, and so SMART claims that the CS-3X, Jr. works well with any film. This means that the component should be able to heighten the sense of spaciousness and envelopment with surround sound.
The front panel consists of a pushbutton power switch, a "CENTER FILL" control knob, which sets the level of the back surround channel relative to the left and right, and a pushbutton which engages ("CS-3X") or bypasses decoding ("LS-RS"). There is also a red LED, labeled as "PRESENCE", which illuminates whenever signals exist within the input left and right surround channels can be steered to back surround.
The rear panel consists of eight gold‑plated RCA jacks, as well as speaker level inputs from the left and right surrounds. The RCA jacks consist of left and right surround input, left and right surround output, the back surround output ("CS OUT"), two "special " outputs for possible future applications (which are equivalent to the conventional surround outputs from Circle Surround decoding of 2-channel material), and a subwoofer output (via a lowpass filter, -3dB at 125 Hz and 12dB/octave rolloff). Indeed, the CS-3X, Jr. is actually a full-fledged 5.1-channel Circle Surround matrix decoder!
There are also trim pots on the rear panel to adjust the levels of each of the channels, as well as individual DIP switches for each channel to engage pink noise for level balancing. The only level that should need to be adjusted is the back surround output, which can be fine‑tuned by adjusting the "CENTER FILL" knob. This calibration process is likely to be easier with two people, especially if you're using a meter to measure the sound pressure level at the prime listening position. SMART suggests that the level for the back surround channel be 3dB higher than the left and right.
For evaluation purposes, a variety of material was played through the system, with CS-3X decoding engaged. Two Dolby Digital Surround EX encoded titles, Austin Powers: The Spy Who Shagged Me and The Haunting, sounded downright impressive and exciting with three surround channels. A greater sense of spaciousness was usually subtle, but definitely evident. Also, when specifically called for, sounds were steered to back surround. As noted in a previous feature in WSR (see Issue 35), the CS-3X. Jr. seemed to perform in much the same way as a THX Surround EX TM - component.
The CS-3X, Jr. was
particularly interesting with non EX‑encoded films, and several such
titles were evaluated with the unit. The decoding seemed to work very well with
parts of Apocalypse Now, such as the very beginning of the film when you hear
the sounds of a whirling helicopter blade circling around you. As the sound
passed behind you, there really was a sense of the CS-3X, Jr. filling in the
gap present between the left and right surrounds. With a few other films, such
as The Mummy, the Circle Surround
decoding seemed to open up the
surround soundfield, and there were even
some instances of the decoder responding accordingly to visual events passing
over your head. The results with the CS-3X, Jr. are, of course, dependent on
the film, so much experimentation is needed. For most movies, we found that the
component helped to impart a slightly greater sense of spaciousness in the
surrounds, while maintaining good channel separation between left and right.
The CS-3X, Jr. is a nifty home theatre component that can be used both for decoding of Dolby Digital Surround EX soundtracks, and for any soundtrack which might benefit from some processing to extract a real center surround sound image. At $299 for what is a full-featured Circle Surround decoder, what are you waiting for?
SMART Center Surround 3X (CS-3X, Jr.) Inputs (2): Gold plated line level & speaker levels - Outputs (6): Gold plated line level Trim pot level controls for each channel "CENTER FILL" control for back surround channel level; individual channel pink noise generators Dimensions: 8.6" W x 2.00" H x 6.25" D Weight: 3.5 Price: $299
SMART Devices, Inc.
5945 Peachtree Corners East
Norcross, GA 30071
Phone: 800 45 SMART / Fax:
770 449 6728
Dolby Digital Surround EX and
Prologic are trademarks of Dolby Labs, Inc. San Francisco, CA.
Circle Surround is a
trademark of SRS, Labs, Inc. Santa Ana, CA.
THX Surround EX is a
trademark of THX Div. of Lucasfilm Ltd., San Rafael, CA.
Rear view of CS-3X, Jr.
This review is published
with permission of Wide Screen Review magazine, Temecula, CA.