Denon AVR-X8500H vs Onkyo TX-RZ840 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Denon AVR-X8500H has 13.2 versus 9.2 for Onkyo TX-RZ840. Regarding power, then AVR-X8500H has such a W/Ohm ratio - 150/8, 250/6 when TX-RZ840 has a power of 180/6. The THD is 0.05% for the AVR-X8500H but 0.08% for the TX-RZ840.
Characteristics of digital to analog converter (DAC) are different, AK4490EQ 768 KHz/32-bit for AVR-X8500H and AKM 384 KHz/32-bit for the TX-RZ840. Both the AVR-X8500H and the TX-RZ840 support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Both models have the ability to connect to the Internet via WI-FI. 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 AVR-X8500H can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, and the TX-RZ840 can receive a content from Deezer, TIDAL, Pandora, TuneIn Radio. 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. The AVR-X8500H can scale the input HDMI signal, unlike the TX-RZ840. The HDR standard - Dolby Vision is supported by these receivers.
The Denon AVR-X8500H has 8/3 HDMI inputs/outputs versus 7/2 HDMI connectors of the Onkyo TX-RZ840. 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. Both models support the standard HDCP 2.2. These compared receivers have a built-in phono stage for connecting a vinyl player.
Each of the AV receivers from our review supports 3 Multi-room zones. The AVR-X8500H supports voice control via Amazon Alexa, Google Assistant, Siri, Josh.AI, and the TX-RZ840 - Google Assistant. An ECO mode is only available for the AVR-X8500H. Both AVR-X8500H and TX-RZ840 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.