It makes sense comparing Pioneer VSX-S520 vs Onkyo TX-RZ710 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Pioneer VSX-S520 has 5.1 versus 7.2 for Onkyo TX-RZ710. Regarding power, then VSX-S520 has such a W/Ohm ratio - 50/4 when TX-RZ710 has a power of 175/6. The THD is 0.09% for the VSX-S520 but 0.08% for the TX-RZ710.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for VSX-S520 and AK4458 384 KHz/32-bit for the TX-RZ710. Only the TX-RZ710 supports Bi-amping feature. 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. Spotify can be used on each receiver. The VSX-S520 can work with the audio stream from Deezer, TIDAL, TuneIn Radio, and the TX-RZ710 can receive a content from Deezer, TIDAL, Pandora, Tunein Radio.
These units support HDR technology. 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. Dolby Vision technology found support only on the VSX-S520.
The Pioneer VSX-S520 has 4/1 HDMI inputs/outputs versus 8/2 HDMI connectors of the Onkyo TX-RZ710. The HDMI Audio Return Channel (ARC) feature supports both devices. Unfortunately, HDMI eARC is not available on monitored devices. 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. A voice control is not available. An ECO mode is only available for the TX-RZ710. The setup assistant will help you configure Pioneer VSX-S520.
Both devices have support for Dolby Atmos multichannel audio format. The surround sound technology DTS:X is supported by devices under review.