I am able to get a really thick sub sound two ways. 1.) My POG2 octave pedal with the -2 octave mixed heavily over the dry signal. 2.) I also have the old Boss super shifter with the dive bomb setting to -1 octave. The super shifter gives you a true sub sound, and the POG has much more presence due to the dry signal mix capability. It is also very helpful to scoop the mids a little.
ZWKoch, S.A.S.S. #124; Fuzzrocious #150; Club Verellen #20; Five String Bass Club #558, Wisconsin Bassist #137; Club Microtubes #7; fEARful #91.