Having had an opportunity to test Pioneer VSX-531 vs Onkyo TX-NR616, I’d like to share my impression here to facilitate your choice of a new AV receiver.
The number of channels for receivers is different - 5.1 versus 7.2, respectively, for devices. In terms of power, there are differences, the VSX-531 has such a ratio W/Ohm - 80/8 20Hz-20KHz, 140/6 1KHz, while the TX-NR616 has a power of 160/6 1KHz. A common feature for devices is the same total harmonic distortion - 0.08%.
The manufacturer installed different DACs, the VSX-531 received the model 192 KHz/24-bit, but the TX-NR616 is equipped with Burr-Brown 192 KHz/24-bit. The Bi-amping function is implemented only in the Onkyo TX-NR616. Both Pioneer VSX-531 and Onkyo TX-NR616 can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Wireless Internet connection via WIFI is only possible with TX-NR616. Each of the receivers has a Bluetooth connector. Support for Apple Music Services not implemented. The TX-NR616 has access to the Spotify service.
Support for the HDR function can only boast of the VSX-531. The quality of 4K 60p signal remains unchanged when transmitting from a source to a TV or projector via HDMI for both receivers. Signaling over HDMI in standby mode can provide the VSX-531 and the TX-NR616. Video scaling is only possible with the TX-NR616. Review participants do not have the Dolby Vision feature.
The number of HDMI inputs/outputs varies depending on the receiver, the VSX-531 has 4/1, and the TX-NR616 has 8/2. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the VSX-531 and the TX-NR616. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. VSX-531 and TX-NR616 support the standard HDCP 2.2. Unlike most receivers, our models do not have a built-in phono stage for connecting a vinyl player. Voice control of the basic functions of the receiver is not realized in both models. There is an ECO mode in VSX-531. None of these units can be properly configured using the setup assistant.
Generally no support for a Dolby Atmos multichannel audio format. A DTS:X surround technology is not supported by devices from our comparison.
The Onkyo TX-NR616 is better receiver in this comparison. Check Onkyo TX-NR616 price