Dual Opposed Sub in corner

[Willem]

I have one dual opposed sub, a B&W PV1d that is currently positioned in a corner. I also have a small Kef Kube 8b that I will probably locate on a shelf on a side wall, and I am planning to buy another (larger) sub for a Geddes style multisub set up. This article at Data-Bass https://data-bass.com/#/articles/5cb4eb62079a580004e73249?_k=xzimh4 suggests that one advantage of dual (or triple) opposing driver subs is that the in-room response is spatially averaged somewhat (apart from the smoothing from multisub arrangements). What I am wondering about is whether this advantage of a dual opposed sub disappears or is seriously diminished by locating such a dual opposed sub in a corner, with the drivers facing the side walls at 45 degrees. If this is indeed the case I might as well buy a cheaper single driver sub for the corner position and locate my dual opposing PV1d somewhere in the room with some free space on either side. After all, dual opposed subs tend to be relatively more expensive.

[dbstedt]

Dual opposed will reduce the majority of cabinet vibration due to the drivers moving mass acceleration but it shouldn't affect the output response unless the distance between drivers is 'large' or the frequencies you're running at are 'high'. 

I would start by putting your largest sub in the corner (highest low-fq output) and work from there. 

Please send updates or measurements if you have them and best luck in handling your room modes.

[Willem]

I understand the vibration advantages of Dual Subs, and also that for the best in-room response multiple subs are the road to go. However, the article that I linked to also claims that dual opposed subs have a spatially more uniform pattern, and that is what I am after.

Below is an REW measurement of the in-room response of the Kube8b, positioned in the front left corner of my large listening room, and equalized with a DSpeaker Antimode 8033 (only for the subwoofer). I used multiple listening positions for the equalization, so response at the main listening position is not as smooth as I could have achieved by equalizing for just one position. The main speakers are Quad 2805 electrostats, high passed at 80 Hz with a fourth order filter. As you can see response reaches pretty low for such a small sub, probably due to the combination of a corner position and a large room size. The PV1d went down even lower and was effectively flat down to 14 Hz. The additional subwoofer that I am contemplating is a KEF Kube12b.