Actually you don't need any extra cables if you want to connect both front speakers to buttkicker amp. Just plug in both red and black RCA plugs to amp as the manual clearly says that one socket is a duplicate of the other to allow " Daisy chain connections". But if you connect it this way you compromise's the stereo affect of your sound system because you connect both speakers parallel. I have connected my Buttkicker to my subwoofer out and kept the system volume constant around 80% and control the volume by the remote controller of the sound system. This way you can get all the vibrations and keep the vibrations of buttkicker constant even if you control the sound.