Originally Posted by NuSoardGraphite
I have mine about 8" from the wall (circumstances require it). Is that close enough, or should I move them further back?
I assume the back of the cab is 8" from the wall. If the cab is a foot deep that places the baffle 20" from the wall. 20" is 1/4 wavelength at 170Hz, so that's the center of the cancellation dip. If the baffle is a foot from the wall that's 1/4 wavelength at 280Hz. That will be a lot less noticeable than 170Hz or lower.
The alternative is to pull the speakers further away, putting the dip below their passband. That's a problem with towers that run full range. If you want to have the dip down at 35Hz the distance from the baffle to the wall would have to be 8 feet. But with a sub crossed at 80Hz and bookshelves on stands a four foot distance from the baffle to the wall puts the dip at 70Hz., below where the bookshelves function, while having the subs two feet from the wall places their dip at 140Hz, well above where they're working.
Another option with bookshelves is to make them true bookshelves, by placing them on shelves and surrounding them with books that come out to flush with the baffle, and then there's no dip.