3Com CP-1 owner manual Theory and Design

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Theory and Design

Lexicon

sound does not. Occasional extra wide sound effects can seem peculiar at first for being so much wider than the screen but when the mix is good the emotional impact of the wide sound can be very great. The disparity between the size of the video screen and the size of the sound is usually easy to accept, and the added impact is hard to give up once you have heard it.

A few theaters are beginning to wake up to the power of this effect. It is being used presently and has been used in the past. Some theaters, such as Imax and Omnimax, use it routinely with multi-track masters, and older tech- niques such as Todd-AO had wonderful multichannel soundsystems.

The major reason standard theaters do not use this is the poor accuracy of previous surround decoders when used with commercially available stereo prints. Azimuth errors on both optical and magnetic masters are common and in theaters there can often be considerable dialog leakage into the left and right channels. To increase the seating area with acceptable dialog, theaters place the left and right speakers within the confines of the screen.

The needed spatial impression is supplied by the acoustics of the theater itself, augmented by surround speakers placed all around the audience. The surround speakers are driven in parallel from the surround channel output of the decoder.

The CP-1 can be used to create a similar set-up in the home by connecting the side speakers to the rear amplifiers. However, our experiments indicate that most people find this far from optimal. The use of auto azimuth, auto balance and digital steering make the CP-1 superior to any other surround decoder, including the professional decoder for theaters. This allows us to remove the dialog completely and feed the left and right signals (not the surround) to the side speakers. When side speakers are present this is a marvelous solution. (See speaker configurations 10 and 11, page 13.) Much the same effect as separate side loudspeakers can be provided by simply placing the main loudspeakers near the sides of the listeners and using the center loudspeaker to fill in the middle of the front image.

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Contents Panorama Ambience CP-1 Digital Audio Environment ProcessorOwners Manual Reverb SurroundPrecautions Unpacking and InspectionAcknowledgements Safety Suggestions Table of Contents Controls IntroductionControls Indicators Front PanelSource Monitor Rear Panel InputsRemote Control ProgramsPanorama Parameter VolumeBank EffectControls Indicators Connection Calibration InstallationPrecautions Connections to Other EquipmentConnecting the CP-1 in a Tape Monitor Loop Connection and CalibrationAudio Inputs Connection Calibration Setting Main Input Output LevelsFront Panel Adjustments Input LevelsOutput Levels Balancing Additional ChannelsCalibration of the Panorama Program Silence Noise Speaker Set-Up Configuration ConfigurationSpeaker Configurations Speaker Set-Up Configuration For FilmSpeaker Set-Up Configuration For Music Speaker Set-Up Configuration Speaker Set-Up Configuration Using the 4 Programs Test ModeTo Load, Modify and Store Programs Panorama Program ParametersInput Balance Rear Level Rear DelayEffect Level Listener PositionAmbience Room Shape LivenessPrograms Ambience Reverb Bass RT Pre-DelayMid RT TrebleSurround Program Parameters Mono LogicStereo Logic Pro LogicBass Blend Program Parameters contd Auto AzimuthBalance Rear EffectTo Rename and Store a Register Using ProgramsRestoring Original Settings Naming a RegisterUsing Programs Troubleshooting TroubleshootingProblem Troubleshooting Restoring defaults Troubleshooting Theory Design Lateral SoundConcert Hall Acoustics Theory and Design Lateral Sound in your Listening EnvironmentAmbience Extraction TheoryDesign Ambience GenerationPanorama Program Theory Design Theory and Design Ambience Program Be the sound that comes from the sides Reverb Program Surround Programs Mono LogicPro Logic Dolby Surround Decoding Pro Logic DecodingCP-1 Decoder Stereo Logic Speaker Set-Ups for Pro Logic Theory and Design References Theory and Design Specifications Frequency ResponseOptional Equipment 06/00 Lexicon 070-06619 Rev
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