Huh.... I've heard the 906, 926, and 948 all in the same room. That certainly wasn't the case. The 948 was vastly superior in bass depth and volume. That room was probably 4 times larger than what the OP is working with. Indeed in an anechoic environment they're all going to sound about the same to 55Hz, but the room is going to reinforce the bass more severely given it's size. My room is about 14 by 23 so I can avoid some of the corner reinforcement he's going to be dealing with. I feel in that room those things will still be making decent bass below their -6dB low point. I don't know what the OP wants for bass. I want clear, muscular, fairly balanced bass and in that room I'd put 926's if it was my money. I came real close to doing that when I bought my 936's and only didn't because I knew I'd have a bigger room at some point.
Looking at anechoic measurements of the 936 and 826W, it's obvious that the 826W has half the hump in bass response that the 936 does. I would expect the 926 to perform almost identically to that. I think that reinforces me point.