I know this is the generally correct approach and also indicated in the various links of the first post of this thread, and I too therefore use the same target curve for all speakers in my system (5.1). Going further, it's also true that several Dirac guides suggest creating your own target curve following the normal roll off of our speakers, as noted in Dirac. For the front there are no problems: my mains and central channel (bookshelf with rear reflex) have substantially an identical response in grequency, my surrounds are from the same line, but they are sealed on-wall type, so they obviously have quite a different frequency response both up and down. It would therefore be wrong to think of applying only for them a different target curve from, therefore modeled on their actual frequency response to avoid having an excessively full target curve, where the speakers are not able to push, and at the same time too low, where the speakers have more energy? Obviously, the crossover for these two speakers is also different: 80Hz for mains and center, 90Hz (or maybe 100Hz) for the two surrounds.No, the same target curve should always be applied to all speakers. Besides, the bass boost usually occurs below the crossover, so its impact on the main speakers is minimal.