QSC Audio CX168 Appendix Multiple Speaker Loads in Parallel, Multiple Lo-Z Loads in Parallel

Page 27

APPENDIX: MULTIPLE SPEAKER LOADS IN PARALLEL

Multiple Lo-Z Loads in Parallel:

If each speaker load is connected across the same signal source (the output of the amplifier), then the loads are in parallel with one another. If one of the speakers fails in a parallel-connected system branch, the remaining speakers will continue to operate. If all speaker loads are the same impedance, the total imped- ance of a parallel-connected system branch is the impedance of one speaker load divided by the number of loads in the branch (example: three 8-ohm loads in parallel: 8/3=2.667 or roughly 2.7 ohms, too low to use on the CX168).

It is not recommended to connect speakers of different imped- ances in parallel because power will be divided unequally between them. If you are experienced with mixing and matching speaker loads of varying impedances, no damage to the amplifier will result as long as the total impedance is within 4 to 16 ohms per channel, dependant upon operating mode.

Most PA-type speaker cabinets are provided with two or more input jacks that are wired in parallel. If one cabinet is connected to the amplifier, the load impedance is equal to the one cabinet’s specified impedance. If you attach another similar cabinet to the remaining jack of the first cabinet, the two cabinets are now in parallel with each other and the impedance will be half of the one-cabinet value. Consult your speaker’s documentation for connection details as there are many connection methods in use.

Below are examples of parallel connections of 4, 8 and 16 ohm speakers. 2 and 4 ohm parallel loads are not usable because the parallel impedance of 4 ohm loads will always be 2 ohms or less; this is too low an impedance for the CX168 amplifier.

27

Page 26 Page 28
Image 27
Page 26 Page 28
Contents CX168 FCC Interference Statement Important Safety Precautions Explanation of SymbolsTable of Contents Front Panel Front Panel with Security Plate IntroductionRear Panel Dimensions Mounting Points Supporting the Rear of the Amplifier Installation Unpacking & Rack MountingWhat is Included Rack MountingInstallation Cooling & AC Mains Requirements Fan CoolingAC Mains Connection Setup Setup Setting the Mode Configuration DIP SwitchesModes Setup Setting the Mode STEREO, PARALLEL, or BridgeSetup Mode Switches Clip Limiter and LOW Frequency Filters Clip LimiterLow Frequency Filter Frequency Response Curves Low Frequency Filtering TipsConnections INPUTS- Using the Terminal Block Inputs Connections INPUTS- Using the DataPorts Outputs Stereo and Parallel ModeBridge Mode Connections OutputsTerminal Block Connections Connections OUTPUTS- Using the Terminal Block ConnectorsPower Switch Operation Power Switch and Gain ControlsLED Indicators Operation LED IndicatorsGain Controls Operation Gain ControlsGain Control Security Plate Operation Gain Control Security PlateOperation Using the QSC Dataport Connections DataPort ConnectorsUsing the DataPort What Can I Connect to the DataPort? General Guidelines to using the DataPorts on the CX168Four Room Stereo Feed Applications Typical Application ExamplesOFF Stereo Mode Parallel ModeAppendix Description of Stereo & Parallel Operating Modes Normal Operating Levels Appendix Description of Bridge Operating ModeMultiple Lo-Z Loads in Series Appendix Multiple Speaker Loads in SeriesMultiple Lo-Z Loads in Parallel Appendix Multiple Speaker Loads in ParallelProblem no Sound Troubleshooting no SoundProblem Hiss Output Power in watts SPECIFICATIONSCX168CX168 SpecificationsWarranty Information & HOW to Contact QSC Product WarrantyDisclaimer Page Page
Top Page Image Contents