QSC Audio CX168 Appendix Multiple Speaker Loads In Series, Multiple Lo-ZLoads in Series

APPENDIX: MULTIPLE SPEAKER LOADS IN SERIES

Multiple Lo-Z Loads in Series:

Series connection is where the same signal current flows through each of the speaker loads. The signal goes into one terminal of the first speaker and out its other terminal; then the signal goes into one terminal of the next load, and so on. If any of the speakers in a series-connected branch of a system fails, the signal is prevented from flowing through any of the loads (no sound). Total impedance for series connections is the sum of each of the impedances in the chain (see illustration, below).

Series connection schemes are usually used with “raw” speakers (not often with speaker cabinets) for wiring conve- nience. The exposed speaker connections make this method easy for small “strings” of speakers in one area. Most PA-type

speaker cabinets are NOT wired for series connection ability; consult your speaker’s documentation for connection information.

It is not recommended to connect speakers of different imped- ances in series 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 stereo/parallel channel or 8 to 16 ohms, bridged.

Below are examples of series connections for 2, 4, 8, and 16 ohm speaker loads. Series connections resulting in an impedance of 250 ohms or greater are not recommended.

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