So... We all by now have probably become aware of the debate, science, opinion, and 'gospel truths' around the issue of speaker placement and comb filtering, as well as that applying to mixed speaker sizes. (in case you dont a quick primer is that it the accepted 'wisdom' is that it is best to NOT seperate bass cabinet to different parts of the stage due to sound waves interfering with each other and spiking some frequencies while squashing others, and even better is to vertically align speakers whenever possible. also it is best to stick with matching cabinets, speaker types, and sizes whenever possible for the most predictable and pleasing sound experience..... thats the condensed view...) ANYWAY... question is, does this theory/rule apply ONLY to a single sound source such as the bass, or does it apply as well to multiple signal sources? in other words, I know if I put one bass cab on one side of the stage and one on the other there are potential and real sound problems that can arise determined in some ways by the shape and size of the room, BUT... Do those same issues arise by having one bass cabinet on one side of the stage and one guitar cab on the other? for example, lets say the comb filtering model shows that two bass cabs X distance apart would spike the frequency of 30hz and kill 500hz at 50ft out, would those same frequencies be affected the same way if the guitar and bass played matching notes at the same time and the guitar cab is in place of the 2nd bass cab? ( and im just pulling random number here for an example that are probably not accurate... but run with it please ) now lets have a good clean fight.