The Onkyo 494 does have a large and small speaker option (with crossovers at 80 and 120 hz, respectively). There is a subwoofer control button on the front panel that has three options when you press it: off, large speakers, or small speakers. If you have a sub hooked up to the pre-out I don't think it's even possible to have power to the sub without either large or small speakers being selected. hope that's helpful to you.