You seem to have deep placement issues causing some frequencies to be much louder and some much lower. The pink noise being the sum of many frequencies, it is just a guide. Try the tones from the following link (with your SPL meeter).

http://www.realtraps.com/test-cd.htm

That might give you a more accurate picture of what is really happening with low-frequencies in your appt/house and also a more precise tools to see exactly how moving subs and furniture around (and also playing with x-over) will influence/improve things.

But you made the best first move: get an SPL meeter! \:\) Now the fun begins! ;\)

See Mojo's signature