Sorry, did'nt read all the posts but i ve built a few enclosures for a 12w7 28, and jl s spec box at 32.. Most company boxes are designed to be very practical and for all types of music but jl s 32 hz box sounded alot better and cleaner than the one tuned to 28 hz(i know its a lil low for a single 12) But the w7 plays so good at low frequencies anyways i think tuning a little higher will give you much better output over a much wider bandwidth.. Just my $.02 ... And I dont even know why they recommend a 500/1 for anything with a w7 label on it above a 10 inch.. I know the rating s and all but anything 10w7 and up you'll definately want 1000 rms