You need to raise the volume on the sub itself(it has a volume knob) to at least half, maybe 2/3.
Re-run your Audyssey. If you have to, after Audyssey is done, move the subwooofer to 80hz, but leave the other five wherever Aud puts them.
Matter of fact, if it were me, I'd ignore Aud altogether.
Find out what the LOWEST Hz your other 5 can achieve, and set the crossover "with-in" 10hz higher (meaning if 53hz, set 60...if 64hz, set 70).
Set the subwoofer crossover at 80hz, no matter what.
Then with a simple SPL meter($40-$60) you can find the "real" volume rather than what you think. Run the test tone to all 6 individually to match the same level in the SPL from all 5 speakers and sub.
Edit...take my "don't use Aud" with a grain of salt. I don't like ANY auto correct software. I prefer to do it myself. With online resources, and a SPL meter, you can get better results.