Hi Hansang,
As pmbuko correctly pointed out, the reason we changed the instructions in the EP500 manual was to take into account some experiments and listening tests that Ian Colquhoun and Tom Cumberland of Axiom did with the EP500's crossover set to bypass and compared those with the crossover set to 80 Hz or somewhat higher.
The rationale behind this was that the "brick-wall" nature of the DSP filter in the EP500 might cause a sag in frequency response between 100 Hz and the integration of the satellite speakers. I didn't participate in the tests and when I tried it with my own EP500, using both M22s and M80 v2s, I couldn't discern any difference. However, I trust Ian and Tom's conclusions.
I suggest you try it both ways, with the EP500's crossover set to bypass and your AV receivers bass management set to 80 Hz, and then with the EP500 crossover set to 80 Hz or higher together with the AV receiver at 80 Hz. Listen to the bass region between 80 Hz and 150 Hz to see if there's any difference.
Regards,
Alan
