Most speakers won't even reproduce the fundamental frequencies of a bass in drop A tuning.
You might be better off doing the Deftones thing - the guitar parts on the low A string are played in the same octave by the bass (on the 3rd of the 4 strings) and then the bass player plays the low string when it's appropriate (usually when the guitar is playing higher chords). This makes things nice and balanced, and the bass can actually have some tone instead of sounding low and flubby.