I agree with you two, especially the "almost never" part.
Anyway, I want my three front speakers to track as closely to eachother as possible! They're identical & I want to keep it that way (impedance, anyone?).
As long as the subwoofers are crossed over at the same frequency...
Can I connect the amp's center channel through both subs & then to the center speaker without any major problems arising?
That's four wires coming out of the amp's center terminals, one pair going to each sub, being filtered, & then all four wires being terminated into two terminals on the center speaker. I'm not sure if I'm going to have signal issues, thought I am more sure that I shouldn't have any. I'd like to be 100% sure before I spend a small fortune on sixty extra feet of wire, a butt load of banana plugs, a pair of stands & another subwoofer.
Otherwise, the next best place to put one sub is in the ceiling corner, front or rear wall & center.
Based on the collected information, I've drawn up this model with sketchup.
As you can see, the subs are positioned on opposite walls. I simply want the bass to occupy both ears, rather than dominating one (as this is the best position (either side) for flat bass reproduction in this particular space.
From the listening position (center, 2'8" off the floor) REW's room simulator generates this graph for the subwoofer placement depicted above.
I am aware that there is no "stereo" at LF, but I did explain why this isn't entirely true for my case in particular.
I don't really want to get into the science behind why certain frequencies are perceptively radiating from the one subwoofer, placed to my right, just above ear level, which causes wide modal resonance centered at a post 90 Hz frequency. No, that's not my question. I totally understand why that's happening, but thanks anyway.
Using this layout, I've reduced the modal distortion caused by the room dimensions to a single frequency. Other than this one frequency the only issue is that the bass resonates from the rear right corner & noticeably diminishes as it travels through my head, bounces off the opposite wall & back into my left ear. Perhaps this wouldn't be an issue if I were a ghost, but spectral mass I am not & a lot of those frequencies are prevented from reaching my left ear because they are being absorbed (by me) before they have a chance to bounce off the left wall.
This is why I am adding a second subwoofer & that is why I've decided that these frequencies should be sourced from the left & right channels. I don't want these subwoofers playing the LFE channel. For that, I was thinking something more like this: