I'm not familiar with this processor and the manual seems very brief in general. The calibration seems limited to channel volume only. Considering the ease of the calibration process you might want to re calibrate after any changes to the system. The newer room correction programs use not only volume but equalization and delay.
At the advent of 5.1 there were no channels labeled "rear" just surround. Typically the surround speakers were designed to project their sound to the forward and rear of the enclosure. The placement for these "surround" speakers was typically behind the listener but on the side wall.
The codecs have progressed to include a matrixed rear or 6.1 and now discrete left and right rear channels 7.1. These changes eliminate the need for the "surround" style enclosure to a typical forward firing speaker. Moving the surround speakers location much closer to the side of the listening position and rear channels behind or on the rear wall creates the full effect.
When using a 7.1 processor with a typical 5.1 set of speakers the surround channel should provide the best surround effect. The manual should be clear on this point, if not call the manufacturer. There may even be a setting for this configuration.
At the advent of 5.1 there were no channels labeled "rear" just surround. Typically the surround speakers were designed to project their sound to the forward and rear of the enclosure. The placement for these "surround" speakers was typically behind the listener but on the side wall.
The codecs have progressed to include a matrixed rear or 6.1 and now discrete left and right rear channels 7.1. These changes eliminate the need for the "surround" style enclosure to a typical forward firing speaker. Moving the surround speakers location much closer to the side of the listening position and rear channels behind or on the rear wall creates the full effect.
When using a 7.1 processor with a typical 5.1 set of speakers the surround channel should provide the best surround effect. The manual should be clear on this point, if not call the manufacturer. There may even be a setting for this configuration.