You want fast musical sub, and that is a challenge for less than $500. What comes to mind is Pinnacle Subsonic (two 6.5" drivers & 350 watts), available for maybe a little more. Another option would be HSU VTF-Mk2, whick sells for about $500 (one 10" driver and 350 watts). While not matching the performance of a REL, these should blend pretty well with the right placement and provide you with good results. Good luck!
Sub for Totem model 1
Hi I have Totem model 1's with muse 100, melos sha 1, mac hard drive into squeeze box2 into ack dac 1.3 would like to get a sub, any recomendations? Can this be done for 500$? Thanks