Plug a speaker cable from your LOW FREQUENCY power amplifier into the input located on the jackplate of the PS-215S. To properly utilize the PS-215S, you should supply an external crossover to direct mid and high frequencies to another speaker system. A typical system would include an electronic crossover and two power Amplifiers, so that one amplifier is dedicated to only low frequencies, and the other amplifier to only mid and high frequencies. The PS-215S should then be connected to the low frequency amplifier, and the other speaker system to the high frequency amplifier. (Refer to the illustration below.) If the PS-215S is used to supplement another speaker, it may be connected in parallel; however, the PS-215S is limited to low frequencies and will not produce usable high frequencies. The performance of a system set up this way will not be as satisfactory as a biamped system, and the amplifier must be able to drive the total load presented by the two speakers in parallel.