subwoofer connection

Ok thanks.  I think my set up may be a little different.  I have a dedicated mono amp (3) for each speaker except the surround speakers that are tied into a 2 channel amp.  I don't use the subs (2) except for 5.1 home theater and video games. The front speakers magico have plenty of bass for music I believe down to 20HZ.  Previously the back sub was hooked up to the A/V processor via long run XLR as is the 2 channel  amp that powers the two surround speakers.I just thought by connecting the the back sub to the two channel amp and eliminating the long run of wire to it may be more efficient.  But now I am wondering if I have to go into the A/V processor and make some type of adjustment to the two channel so the low frequency signal is set to the amp for the amp output that sends the signal to the sub.  Does that make any sense? Thanks

Thanks for your response.  Okay let me ask about a two sub configuration.  The one sub, I will call it front sub, is located within 2 feet of the processor and the other sub, I will call back sub, about 18 ft from the A/V processor currently connected by about 25 ft balanced XLR.  The back sub is located about 3 feet from the amp, Macintosh 452. that powers the two surround speakers.  Would it be better if the A/V processor only recognized, through the speaker set up menu, the front sub and  reconnect the back sub via short XLR to the MAC 452? Thanks