Start by counting displays. The X1800H suits a single TV and a 5.1.2 speaker system. If you use the TV by day and roll down a projector screen at night, the X2800H gives you a practical reason to upgrade with its second HDMI output.
Wiring a TV and a console
For 4K/120, connect the console to an input marked 8K and the TV to the Monitor output with eARC. Audio from the TV’s own apps can travel back down that cable. Check that the TV and both cable runs support your chosen video mode. On the X1800H the high-bandwidth inputs are HDMI 4, 5 and 6.
Where the seven channels go
Either receiver can run five ear-level speakers, a powered sub and two height channels for 5.1.2. In 7.1 the rear surround pair takes the place of the heights. If you want seven speakers around the sofa and two overhead at the same time, plan for nine amplified channels.
Power or a second display?
Denon rates the receivers at 80 W and 95 W respectively into eight ohms with two channels driven. That difference does not double loudness. With no projector on the horizon, weigh the upgrade cost against a better-matched centre speaker, which carries most film dialogue.
Models in the catalogue · Denon AVR-X1800H · Denon AVR-X2800H
Sources · Denon AVR-X1800H · Denon AVR-X2800H