Texts>Newbie to HT. Have RP-5's, RC-3, RS-3's, Marantz SR7000, Pioneer Elite DV-09. RP's are only connected via monster cable to binding posts. Not sure about LFE hookup?? Room is 14X20 with vaulted ceilings.I love the current sound, but would like some added punch. Can an extra sub be added? If so, any suggestions and how to connect.Thanks!