Ideally you would set the 7000 sub to the 'AV' position and then set the individual crossover frequencies on your home cinema amplifier. If you are able to do this then set the centre, front left and front right speakers to 80Hz and the rear speakers to 150Hz.
If your amplifier doesn't allow different settings for the front and rear speakers then set the sub to AV and all the other speakers to 150Hz.
The 'variable' crossover control on the sub is generally only used with a stereo (not home cinema) amplifier.
Steve Reichert - PR Manager. Armour Home (Q Acoustics)