The room is in control of bass. You can leave it to the magic of Audyssey and hope it's results are satisfactory (which your measurements, are not) or get out a tape measure and start measuring ALL of the parallel boundaries of your room.
1131(feet per sec) / measurement (in feet) = Room Mode - which will measure as a peak or null at the LP depending on it's +/- phase cycle - subwoofers are pressure sources, placement is everything
Frequency + Amplitude + Q = DSP Filter.
(center of peak or null) + (dB increase/decrease to reach relative level) + (bandwidth of resonance measured in hz) = DSP Filter
Those 3 parameters allow you to create a DSP filter to overcome the natural response of producing frequencies that are larger than the dimensions of your room. (20 hz = 56.5 feet for example)
Measurements MUST be taken as 1/24 octave so that nothing is masked. Windows and doors allow flex in boundaries which will lower the measured resonance frequency from predicted. But when you know which boundaries are influencing a frequency, the orientation of subwoofer(s) at that boundary allows you to constructively or destructively drive the standing waves.
If you're really serious and want to learn more, 'Sound Reproduction' by Floyd Toole is the textbook on the subject. He just released the 3rd edition so be mindful which one you order. This is a lifetime of research backed by double blind testing with only minimal mathematics being presented, such as what I've suggested.
