Yamaha RX-V581 vs Onkyo TX-RZ840 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Yamaha RX-V581 has 7.2 versus 9.2 for Onkyo TX-RZ840. Regarding power, then RX-V581 has such a W/Ohm ratio - 115/6 when TX-RZ840 has a power of 180/6. The THD is 0.09% for the RX-V581 but 0.08% for the TX-RZ840.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 192 KHz/24-bit for RX-V581 and AKM 384 KHz/32-bit for the TX-RZ840. Both the RX-V581 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 Yamaha RX-V581 has support for AirPlay, and its competitor in our comparison - AirPlay, AirPlay 2. Spotify can be used on each receiver. The RX-V581 can work with the audio stream from Pandora, JUKE, 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. Both competitors are not able to scale the HDMI signal. Dolby Vision technology found support only on the TX-RZ840.
The Yamaha RX-V581 has 4/1 HDMI inputs/outputs versus 7/2 HDMI connectors of the Onkyo TX-RZ840. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the TX-RZ840. 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. The TX-RZ840 has a built-in phono stage for connecting a vinyl player.
The RX-V581 supports 2 Multi-room zones, versus 3 for the TX-RZ840. An ECO mode is only available for the RX-V581. Both RX-V581 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.