The 5.1.2 surround format starts with the same speaker configuration as 5.1 but adds two overhead side channels (left top mid and right top mid), placed left and right above the listening position. The 5.1.2 channels are left, center, right, left surround (left rear), right surround (right rear), left top mid, right top mid, and LFE.
The 7.1 Sony Dynamic Digital Sound (SDDS) surround format starts with the same speaker configuration as 5.1 but adds two speakers (left center and right center). This is designed for use in a cinema equipped with Sony decoding and playback hardware. The 7.1 channels are left, center, right, left center, right center, left surround (left rear), right surround (right rear), and LFE.
Logic Pro Instruments: PDF