Forgive the title for its length. I have the non-2.0 Xonar Essence STX soundcard in comp with some HD650 headphones and Fluid Audio F5 Monitors for output - question is, is it possible with this configuration to add a subwoofer into the mix? And at that without any additional hardware? Audio sounds sexy enough through the 650s already with the STX, but when producing beats a sub could come in handy when using the Fluid F5 Monitors I believe (the Fluids don't have that low end below 49Hz so it sounds somewhat lackluster as opposed to the 650s). Thx for any input.