How do you do that?

Can you please explain what you mean by 'roll off'.
I went thru the manual and it does not have a setup that says MCACC as such. It has Normal surround setup and Expert setup. The details I have posted below:
Setting Up for Surround Sound
SURRBACK SYSTEM (Surround Back System) ...... 35
NORMAL setup
SPEAKER SETTING .............................................. 37
CHANNEL LEVEL (channel balance) ................... 39
CHANNEL DELAY ................................................. 40
Expert Setup
CROSSOVER NETWORK ...................................... 80
FINE CHANNEL LEVEL ......................................... 81
FINE CHANNEL DELAY ........................................ 82
ACOUSTIC CAL EQ ............................................... 84
BASS PEAK LEVEL ............................................... 86
DYNAMIC RANGE CONTROL .............................. 87
Please tell me which type of setup that I have to play with to roll off the high end.
Thanks very much.