I've tried that combination before and always unplugged the 115 and just went with the 410he because I didn't like both together. However, it is possible to make a 410/115 cab rig that suffers from minimal phasing problems, and many companies do take mixing cabs into consideration in their separate designs. Plus if people likes that combination, there's nothing in it for a company to talk people out of it. So I'd say a little of both.Mixed cabs - Here is what Ampeg says on their web site about the SVT-15E speaker cab: "Team it up with the SVT-CL head and an SVT-410HE, for top-end, and you’re guaranteed to get the dance floor moving". and, about the SVT-410HE cabinet: " The Ampeg SVT-410HE is also the ideal enclosure for the player who wants to add extended upper register clarity to a system that already features ample low frequency performance. Just ask George Clinton—he uses an SVT-410E to round out the top-end of his killer, all-SVT stage setup"......... Sooooo... are Ampeg's comments legit or are they just trying to sell cabinets (or maybe both?)