I have a Cambrige Audio C500 and P500 that I am using to power a pair of M22s...I would like to add a sub to relieve the M22s from producing sub 60hz audio. Am I correct in assuming that I will have to connect the preamp to the line in on the sub and the line out on the sub to the amp for this to work? Would the crossover on the EP 175 be up to this task (is the circuitry clean enough)?