@mswale , if OP hooked up to both of his subs from amp + to + and - to -, and then he went from his subs to his speakers in the same manner (+ to + and - to -) is there any reason that his subs (or speakers) would be out of phase with each other? That is a serious question; OP did report that he felt that things sounded "thinner."
@immatthewj not always the case. My HT subs are hooked up LFE to my receiver. Only other plug is the wall outlet. When I swapped out my HT receiver, and was doing the room correction. It was telling me my subs are out of phase. Checked the phase switch, both pointing up. Then I flipped one, and they were in phase, but out phase with the front channels. So swapped them the other way, and was good to go. Same went for one of my Dolby Atmos speaker, it's wired internally backwards, been listing to this way for years with out knowing.
You never know, and they need to be tested, it's easy....
Turn on the subs, play some bass...
Then turn your balance to the R, listen, then to the L, listen, back to center.
If the bass is loudest at center they are in phase, if not, they are out of phase.
