This document is the instruction manual for the STR-DG800 2CT Multi Channel AV Receiver, released by Sony Corporation in 2006. It explains the fire and electric shock safety precautions to be taken when using the device. It also introduces the Dolby Digital, Pro Logic Surround, and DTS Digital Surround System audio technologies, as well as the HDMI technology it possesses. The document includes instructions for preparation work, speaker installation, connecting audio and video devices, connecting antennas, preparing the receiver and remote control, selecting speaker systems, auto calibration, and adjusting speaker levels and balance. Finally, it explains how to choose and use audio and video components and how to navigate menus.