Most of the Infinity speakers such as the RS-II had very good deep bass. Try them out but I doubt that a sub will be needed. Sub woofers were a necessity after the physical size of speakers started declining to replace the bass that used to be generated from large woofers and large cabinets. These qualify for large cabinet design
My guess is you will be very pleased with them. Bi-amping them would be the next step for sound quality.