An affordable AV receiver is always a good option to consider, so Pioneer VSX-531 vs Onkyo TX-RZ900 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Pioneer VSX-531 has 5.1 versus 7.2 for Onkyo TX-RZ900. Regarding power, then VSX-531 has such a W/Ohm ratio - 80/8, 140/6 when TX-RZ900 has a power of 200/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for VSX-531 and Hi-Grade 384 KHz/32-bit for the TX-RZ900. Only the TX-RZ900 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Only the Onkyo TX-RZ900 can connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. Only the TX-RZ900 supports Spotify.
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 competitors are not able to scale the HDMI signal. The HDR standard - Dolby Vision is not supported by these receivers.
The Pioneer VSX-531 has 4/1 HDMI inputs/outputs versus 8/2 HDMI connectors of the Onkyo TX-RZ900. 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. The TX-RZ900 has a built-in phono stage for connecting a vinyl player. A voice control is not available. An ECO mode is only available for the VSX-531. The setup assistant will help you configure Onkyo TX-RZ900.
Only the TX-RZ900 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-RZ900.