My bass is a cheap old Fernandes active P/J with 4 knobs. I play hard rock with picks, and I want the sound to be low, rough and as clear as possible. I'm planning to get a SD SPB-3 and a SJB-3, but it might be a little bit of "waste" put them on 1 bass.(or is it not?) But since I usually open both pups at the same time, it might be better to get a pair of them at a time. Any suggestions? THX and sorry for my poor english.