Marantz SR6014 vs Onkyo TX-RZ840 comparison definitely makes sense.
Considered AV receivers have the same number of channels 9.2. Regarding power, then SR6014 has such a W/Ohm ratio - 110/8, 185/6 when TX-RZ840 has a power of 180/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, AK4458 384 KHz/32-bit for SR6014 and AKM 384 KHz/32-bit for the TX-RZ840. Both the SR6014 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. 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 SR6014 can work with the audio stream from Deezer, TIDAL, Pandora, TuneIn Radio, iHeart Radio, and the TX-RZ840 can receive a content from Deezer, TIDAL, Pandora, TuneIn Radio.
Both AV receivers support HDR10 technology (High dynamic range). 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 SR6014 can scale the input HDMI signal, unlike the TX-RZ840. The HDR standard - Dolby Vision is supported by these receivers.
The Marantz SR6014 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. The SR6014 supports the protection of digital content of the standard HDCP 2.3, versus HDCP 2.2 in the TX-RZ840. These compared receivers have a built-in phono stage for connecting a vinyl player.
The SR6014 supports 2 Multi-room zones, versus 3 for the TX-RZ840. The SR6014 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 SR6014. Both SR6014 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.