Experimentation is the answer: Since there aren’t any guaranteed best spots when it comes to positioning multiple subwoofers, moving them around and listening for the changes is really the only way to get them locked-in with your lair. But if you have a rectangular room, you can use some general placement guidelines as starting points. Of course, your listening positions will also affect where in the room the subs sound their best. But once you’ve got that dialed in, check out some of the most popular dual subwoofer placement options below:
If you have a rectangular-shaped, dedicated theater room, multiple rows of seating, or just want excellent bass coverage, placing two subwoofers midway along the lengths of opposing sidewalls is the best recommendation. These locations yield the smoothest and most even bass distribution across the widest space due to something known as axial mode cancellation, thereby maximizing bass impact for the most listeners. You can also try placing your bass bins at opposing midwall points across the width if you can’t position them along the length.
No question, loading both subs in the front corners of the room provides the most bass. This is because doing so maximally excites all of the room’s resonances, thereby yielding more output for a given volume setting than ones that aren’t corner loaded. Moreover, you can lower the subs’ volume to increase headroom and decrease distortion. The downside is that corner placement can also provide too much reinforcement: Bass can sound boomy or uneven. If this happens, try bringing them out from the corners in small increments, starting with around one foot of space between each sub and each adjacent wall.
At this point you may be asking yourself, “Is it possible to get the best of both worlds, i.e. bass that’s a blend of both corner and midwall placement?” The answer is a definite maybe: Try positioning your subs along the front wall with their cone centers at the 1/4 and 3/4 distances of the room width. Rooms that are sympathetic with subs at these locations will yield almost as much bass output as corner placement but with a smoother overall frequency response. Of course, this reduces total output compared to full corner placement, but most quality subwoofers nowadays have more than enough headroom to compensate.
Unfortunately, we can’t always place our subs and our chairs in ideal parts of the room due to aesthetic or visual constraints: Many of us simply can’t remodel our room around these items, or have to deal with open floor plans, or irregularly shaped rooms, and the like. Luckily, there may still be a solution—opposite corner placement. Putting the subs in opposing front and back corners will maximally reinforce bass output like the front corners, but can also distribute more linear bass throughout the room. Try tweaking the subs’ positions little by little to see if there are sweet spots where the bass locks with the room. If you’re a bass freak, try this one even if you can do one of the placement options mentioned earlier: You may find this is your preferred bone-crunching, teeth-rattling option.