The Yamaha RX-V4A vs Onkyo TX-NR646 comparison proves that these receivers have many common features.
A significant difference between the receivers in the number of channels, Yamaha RX-V4A has 5.2 versus 7.2 for Onkyo TX-NR646. Regarding power, then RX-V4A has such a W/Ohm ratio - 80/6 when TX-NR646 has a power of 160/6. The THD is 0.06% for the RX-V4A but 0.08% for the TX-NR646. Both the RX-V4A and the TX-NR646 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 Yamaha RX-V4A has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Spotify can be used on each receiver. The RX-V4A can work with the audio stream from Deezer, TIDAL, Pandora, SiriusXM, Qobuz, and the TX-NR646 can receive a content from Deezer, TuneIn Radio. HDMI signal transmission in standby mode is implemented in each of the devices. The RX-V4A can scale the input HDMI signal, unlike the TX-NR646. Dolby Vision technology found support only on the RX-V4A.
The Yamaha RX-V4A has 4/1 HDMI inputs/outputs versus 8/2 HDMI connectors of the Onkyo TX-NR646. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the RX-V4A. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The RX-V4A supports the protection of digital content of the standard HDCP 2.3, versus HDCP 2.2 in the TX-NR646. The TX-NR646 has a built-in phono stage for connecting a vinyl player. It is also worth noting that the ECO mode is presented in each of the receivers. Both RX-V4A and TX-NR646 can be configured using the Setup assistant.
Only the TX-NR646 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-NR646.