It makes sense comparing Yamaha RX-A780 vs Denon AVR-X4400H because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Yamaha RX-A780 has 7.2 versus 11.2 for Denon AVR-X4400H. Regarding power, then RX-A780 has such a W/Ohm ratio - 95/8, 160/4 when AVR-X4400H has a power of 125/8, 165/6. The THD is 0.06% for the RX-A780 but 0.05% for the AVR-X4400H.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 384 KHz/32-bit for RX-A780 and AK4458 384 KHz/32-bit for the AVR-X4400H. Both the RX-A780 and the AVR-X4400H support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
WI-FI modules have the same characteristics: 2.4/5GHz. Rivals from our review have Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay, AirPlay 2. Spotify can be used on each receiver. The RX-A780 can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, Qobuz, and the AVR-X4400H can receive a content from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud. Compared AV receivers retain the quality of 4K/60Hz signal when transmitting from a source to a TV or projector. HDMI signal transmission in standby mode is implemented in each of the devices. Both rivals can scale the resolution of the incoming HDMI signal. The HDR standard - Dolby Vision is supported by these receivers.
The Yamaha RX-A780 has 7/2 HDMI inputs/outputs versus 8/3 HDMI connectors of the Denon AVR-X4400H. The HDMI Audio Return Channel (ARC) feature supports both devices. HDMI eARC is available in each model. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The RX-A780 supports the protection of digital content of the standard HDCP 2.3, versus HDCP 2.2 in the AVR-X4400H. These compared receivers have a built-in phono stage for connecting a vinyl player.
The RX-A780 supports 2 Multi-room zones, versus 3 for the AVR-X4400H. The RX-A780 supports voice control via Amazon Alexa, Google Assistant, and the AVR-X4400H - Amazon Alexa, Google Assistant, Siri, Josh.AI. It is also worth noting that the ECO mode is presented in each of the receivers. Both RX-A780 and AVR-X4400H can be configured using the Setup assistant.
Both devices have support for Dolby Atmos multichannel audio format. The surround sound technology DTS:X is supported by devices under review.