The receive based on the 9 x 100-watt amplifier, which is not very much even against the TX-NR686 (160 watts/channel), bang up-to-date surround processing including DTS:X and Dolby Atmos. TX-NR787 has a power amplifier that has a true class-AB design with a linear power supply. Users can set up a 7.1 surround setup with a single pair of ceiling-mounted or upward-firing Atmos speakers or the TX-NR787 can be used in a regular 5.1 surround setup, freeing up the extra amp channels to drive speakers in up to two additional audio-only zones.
Onkyo TX-NR686 is THX Select certified. This seven-channel AV receiver is equipped with amplifiers manufactured using Dynamic Audio Amplification technology. Due to the high output current, which is provided including through the use of a custom transformer H.C.P.S. in the power supply, Onkyo TX-NR686 can fully swing even 4-ohm speakers. If compare Onkyo TX-NR787 vs Onkyo TX-NR686, the TX-NR686 cannot power speakers in the Third zone. The device has full network functionality, including support for the popular wireless multi-room technology DTS Play-Fi. Over the network, you can play files in all popular PCM and DSD formats.
The Onkyo TX-NR686 is better receiver in this comparison. Check Onkyo TX-NR686 price