And what version of Audyssey was that?
Perhaps that's why the process is called room equalisation....
Audyssey measures the speakers frequency capabilities. It will set the crossover low if the speaker can go low. Only by checking with something like REW can you see if that is better or should be changed.
80hz is a catchall which doesn't suit every room setup or speakers. My room results so far are showing between 100 to 120hz as having less nulls and a flatter response when testing front L/R and 2 subs all together.
I've been using the app in combination with ratbuddssey and checking the results with REW (Audyssey On and Off). Easy to see how good or not a job Audyssey is doing. One useful feature with ratbudyssey is looking at the results from the seperate readings which if tightly done can indicate if it might be worthwhile moving the MLP 6 inches to the side or forwards/backwards etc
Audyssey comes free with the AVR. The app is £20 so is definitely little money in the scheme of things.
Time needs something to fill it with....