5.2.5™ HOME THEATER DECODER
Circle Surround® USER'S MANUAL C. E. Your Circle Surround 5.2.5 Home Theater Decoder has been tested and complies with the following Standards and Directives as set forth by the European Union:
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Council Directive(s): 89/336/EEC Standard(s): EN55013, EN50082-1
This means that this product has been designed to meet stringent guidelines on how much RF energy it can emit, and that it should be immune from other sources of interference when properly used. Improper use of this equipment could result in increased RF emissions, which may or may not interfere with other electronic products. To insure against this possibility, always use good shielded cables for all audio input and output connections. Also, bundle audio cables separately from the AC power cables. These steps will help insure compliance with the Directive(s). For more information about other Rocktron products, please see your local dealer or one of our importers closest to you (listed on the enclosed warranty sheet).
CONTENTS 1. 2. 3. 4. 5.
Introduction Front Panel Rear Panel Setup and Operation Specifications
1. INTRODUCTION Congratulations on your purchase of the Circle Surround® 5.2.5™ Home Theater Decoder! The patented Circle Surround 5.2.5 system is the most advanced matrix surround sound decoding system available, and the Home Theater Decoder brings this technology to the home. The Circle Surround® decoding process improves left/right and front/rear separation, as well as image-positioning, by detecting the relative amplitude and phase relationship within the input stereo signal. Based on this information, the system distributes independent audio signals to each of the five speaker locations (left, center, right, left surround and right surround). The Circle Surround 5.2.5 Home Theater Decoder's Surround Music mode creates a listening environment that places the listener inside music performances unlike any other surround system. Encoding music in Circle Surround allows recording engineers to place sounds or musical instruments at any location the 360° circle created by the five (or four) playback speakers. The Circle Surround Home Theater Decoder maintains complete compatibility with material encoded in other surround formats, and also extracts surround (ambient) information from conventionally recorded stereo mixes on CD, laser discs, cassettes, or broadcasts. Unlike all other matrix surround sound decoders, the Circle Surround 5.2.5 decoder provides full bandwidth, stereo information to the left and right surround speakers (even with program material encoded with restricted bandwidth, monophonic surround information), adding far greater realism to both music and video listening environments. The Home Theater Decoder's Surround Video mode provides performance not available from any other matrix surround sound system. In addition to providing stereo surround channels, the dynamic center channel automatically lowers its level when no dominant center channel information is present. This, coupled with patented steering logic, maintains the stereo information the recording engineer and producer originally intended.
(All other surround sound systems tend to collapse to mono with dominant center channel information, or when the program material gets loud and busy.) The exclusive Circle Surround decoder steering places moving sound effects from an LTRT source where they would be heard when listening to a discrete digital recording. Separation is maintained above 55dB between all front channels and opposite surround channels, and approaches 29dB between the stereo surround channels. The Circle Surround 5.2.5 Home Theater Decoder accepts the LT-RT outputs from any playback device or broadcast receiver and outputs L-C-R-LS-RS and Sub signals to power amplifiers. This user's manual will detail the various functions and applications of the 5.2.5 Home Theater Decoder. Please keep it for future reference.
2. FRONT PANEL
(1) POWER switch (2) NOISE SEQUENCE Switch/leds When pressed, pink noise is generated in each channel in a sequence of left, center, right, right surround and left surround. The OUTPUT TRIM controls can then be used to adjust the level of each individual channel to achieve the desired balance. When the noise sequence is active, any signals connected to the Home Theater Decoder inputs are attenuated so that only the noise sequencer can be heard. (3) MODE select switches/leds These switches determine the current surround mode for the Home Theater Decoder—Surround Video, Surround Music, and normal Stereo mode.
In Surround Video mode, center information is steered exclusively to the center channel, and is high pass filtered to enhance the subwoofer effect. In addition, the center channel operates dynamically based on the level of center channel information at the input, as well as the presence of signals panned hard left or right. A 30ms delay is applied to the surround speakers to enhance the precedence effect. This mode is most effective for viewing films in a theater or home theater environment. In Surround Music mode, the left and right channels remain unaltered at all times. However, the center channel maintains dynamic operation. In addition, there is no delay applied to the surround channels in this mode. Stereo mode provides normal stereo operation, with no output from the center and surround channels. (4) CENTER CHANNEL switch/led This switch determines whether the center channel signal is fed though the rear panel CENTER output (for use with a dedicated center channel speaker), or fed equally to the left and right channels (for use in a four-speaker system not incorporating a center channel speaker). When switched in (LED lit), the Home Theater Decoder operates in "Center" mode, feeding the center channel signal through the rear panel CENTER output to a dedicated center channel speaker in a five-speaker system. When switched out (LED off), the unit operates in "Phantom" mode, feeding the center channel information equally to the left and right channels. (5) SURROUND CHANNELS select switches/leds The SURROUND CHANNELS switches determine the operating characteristics of the surround channels. The BANDWIDTH switch determines the overall bandwidth of the surround channels, and can be set to either 20kHz (full bandwidth) or limited to 7kHz. The SOUNDFIELD switch determines the mode in which the surround channels operate. In the NORMAL mode, rear channel steering is such that audio panned hard left or hard right will be steered to the left or right front speakers only. (The rear channels are attenuated when hard panning occurs in this mode.) In the WIDE mode, material panned hard left or right is steered to its respective surround channel and boosted 6dB. (6) OUTPUT TRIM controls (LF, RF, C, SL, SR, SUB) These controls are used to balance the level of each channel when the NOISE SEQUENCE has been initiated. These levels may also be adjusted when listening to audio.
(Note: The noise sequence is not applied to the SUB channel.) The range of adjustment is from unity gain to -17dBu. It is recommended that you begin with each trim pot turned completely clockwise and turn down to match your speaker channels for optimum level balance and best S/N. (7) CINEMA CONTOUR control The soundtracks on many laserdiscs contain excessive levels of high frequencies. This is caused by the lack of screen loss in most home theater systems. In movie theaters and in cinema mixing theaters, the speakers are placed behind the perforated projection screens. This causes high frequency loss. Most laserdisc producers do not re-equalize ad roll off the high frequencies that are attenuated by these perforated screens. When played back in many home theater systems, the reproduced sound is too brilliant. The CINEMA CONTOUR control allows the Home Theater Decoder user to gently roll off these excessive highs to suit the acoustics of the listening environment. (8) VOLUME control This control determines the overall volume for all outputs.
3. REAR PANEL
(1) INPUT (L and R) connectors These RCA connectors accept the left and right line-level outputs from any stereo source—stereo receiver, VCR, Laserdisc, etc.. (2) SUB OUTPUT connector This RCA connector provides frequencies below 80Hz for connection to a subwoofer.
(3) REAR OUTPUTS (SL, SR) connectors These RCA jacks provide the line-level output signals to be amplified and fed to the left and right surround speakers. (4) FRONT OUTPUTS (C, R, L) connectors These RCA connectors provide outputs to be amplified and fed to each of the front speaker locations—left, center and right. (5) POWER connector This 4-pin DIN accepts power from the 9VAC adapter supplied with the Home Theater Decoder.
4. SETUP AND OPERATION Speaker Location The Circle Surround 5.2.5 Home Theater Decoder is used to its fullest potential when used within a 5-channel system, configured as left, center, right, left surround and right surround as shown in Figure 1 on the following page. Referring to Figure 1, please note the following: • • • •
The three front speakers (left, center and right) should ideally be the model speaker. The left and right surround speakers should also be the same model speaker (or from the same family with like timbre or frequency response). All of the speakers should be placed at the same height, with the center speaker as close as possible above or below the video monitor. A subwoofer is not a required element of the Circle Surround system, but will greatly add to your listening pleasure. If a subwoofer is used, it may be placed in a corner or under a table, as low frequencies are typically difficult to localize depending on the acoustic environment. If localization is detected, placement toward the front-center of the room or below the center speaker is recommended. Some acoustic situations require the use of dual subwoofers to eliminate standing waves and/or localization.
Figure 1 Typical speaker configuration for a 5-channel sound system.
System Connections The setup of the 5.2.5 Home Theater Decoder is dependent upon the features provided by your stereo A/V receiver (or component home theater system), as each of the six outputs of the Home Theater Decoder require separate amplification. Figure 2 on the following page illustrates the use of a dedicated preamp/controller unit which accepts the outputs of all audio devices in the system and allows for the selection of the current device. The left and right outputs of the preamp/controller unit feed the left and right inputs of the 5.2.5 Home Theater Decoder, which then extracts six independent output signals from the LT-RT input signal. As previously stated, each output signal requires separate amplification before being fed to its respective speaker location. The RSP Technologies Surround 600 amplifier (shown in Figure 2) provides six 100 watt amplifiers for surround-based applications. Each output from the Surround 600 can then be fed to its intended speaker location.
Figure 3 (p. 10) illustrates the use of an A/V receiver that incorporates six discrete inputs for use with a surround processor. In this type of configuration, any active LT-RT preamp output may be used to feed the inputs of the 5.2.5 Home Theater Decoder. The six Decoder outputs each have a dedicated input on the receiver. After these signals are fed back to the receiver, they are amplified internally and fed to their respective speaker locations.
Figure 2 Using the 5.2.5 Home Theater Decoder with a Preamp/Controller and 6-channel power amplifier.
Figure 3 Using the 5.2.5 Home Theater Decoder with a receiver which features discrete 5.1channel inputs for use with a dedicated surround processor.
Selecting the Operating Mode The 5.2.5 Home Theater Decoder operates in any of three different modes—Surround Music, Surround Video or conventional Stereo. The Surround Music and Surround Video modes each provide algorithms with patented characteristics for either dedicated music or film applications. The current mode is selected via the front panel Mode switches:
When operating the Decoder in Surround Video mode, dominant center information is steered exclusively to the center channel. In addition, the center channel operates
dynamically to emphasize dominant center information. When wide stereo information is present, the center channel will attenuate by approximately 6dB. Material panned hard left or hard right will result in full attenuation of the center channel. This helps to preserve a broad front stereo soundfield in the Surround Video mode. A 30ms delay is applied to the surround speakers to enhance the precedence effect. If two sound sources produce the same audio material and a small delay is introduced into one of them, the earlier sound source will determine the localization of that sound. The Surround Video mode is most effective for viewing films in a theater or home theater environment. In Surround Music mode, the left and right signal pans remain unaltered at all times. However, the center channel maintains dynamic operation as described for the Surround Video mode, and, as above, material panned hard left or right results in the full attenuation of the center channel. The surround speakers operate as per the front panel Surround Channels settings, however the 30ms delay is disabled. Stereo mode provides normal stereo operation, with no output from the center and surround channels.
Selecting the Sound Field Properties When the Sound Field switch is set to WIDE, signals panned hard left will result in a left front signal at +3dB and a left surround signal at +6dB. This gives the sense of the signal coming from the left rear. As the signal is panned from hard left toward center, the left rear level will begin to decrease while the left front level will begin to increase. When the Sound Field switch is set to NORMAL, surround channel steering is such that audio panned hard left or right is produced only in the front speakers, as the surround channels are attenuated when hard panning occurs.
5. SPECIFICATIONS Nominal Reference Level Input Impedance Output Impedance Frequency Response Dynamic Range Power Consumption Master Volume Level L, C, R, SL, SR, SUB Level (Range) Typical Seperation: L to C C to R L to SR R to SL SL to SR Fuse
-10dB 21K ohms less than 150 ohms ±½dB (typical), 20Hz - 20kHz 115dB (typical) 1.5 Amps from supplied adapter 85dB range unity to -17dB 59dB 59dB 59dB 59dB 29dB 2 amp, slow blow