with 2 subs, SSA Dcon 12's, they have a high sensativity, which I generally don't suggest using for "how hard they hit", but after hearing the output of these on a moderate 300w..im impressed. Also the Dcon has a great sound to it. 500 to 2 would be a tad underpowered but there are not going to be many subs out there you can run 2 of on 500 and get good sound. If you want to limit yourself down to 1 sub, you can still go with the Dcon and give it about 400 of your avaliable 500, giving you some headroom... if you want to use the full potential of the amp, you can always go with an Icon, an SA12 from Sundown, IDQ12 from Image Dynamics, W6 from JL...