I currently have the maganplanar SMGs which are ideal for my small listening space.

In my attempts to integrate a subwoofer with the planars, I've found that subwoofer placement in the listening space is most critical. I don't know if there is any theory to substantiate my findings, but I found that the subwoofer cannot be placed anywhere near the planars at the front of the listening space. The presence of the primary sound energy from the front and its 180 counterpart from the rear of the panel will conflict with the sound energy from subwoofer resulting in muddy bass or offsetting cancellation. (It makes me curious to experiment with some of the dipole Subwoofer designs I've found in many discussions-but that is another topic)

But I found my most successful attempt at integrating a subwoofer has been placement behind my listening position at very low volume levels. It does not seem to collide with any of the cancellation nodes and I cannot perceive any out of phase sound pressure from my listening position. With the volume low, it still fills the lower reaches where my SMGs are weak but I do not perceive its presence nearby. It sounds as if all of the sound energy is eminating from the magnaplanar panels up front.

I don't understand it but if anyone can explain it, I would appreciate the education. It does seem to work.