An affordable AV receiver is always a good option to consider, so Onkyo TX-RZ820 vs Denon AVR-S650H comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Onkyo TX-RZ820 has 7.2 versus 5.2 for Denon AVR-S650H. Regarding power, then TX-RZ820 has such a W/Ohm ratio - 160/8 when AVR-S650H has a power of 75/8, 100/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, AK4458 384 KHz/32-bit for TX-RZ820 and AKM 192 KHz/32-bit for the AVR-S650H. Only the TX-RZ820 supports Bi-amping feature. 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 Onkyo TX-RZ820 has support for AirPlay, and its competitor in our comparison - AirPlay, AirPlay 2. Spotify can be used on each receiver. The TX-RZ820 can work with the audio stream from Deezer, TIDAL, and the AVR-S650H can receive a content from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, Mood Mix.
Both AV receivers support HDR10 technology (High dynamic range). 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 supported by these receivers.
The Onkyo TX-RZ820 has 7/2 HDMI inputs/outputs versus 5/1 HDMI connectors of the Denon AVR-S650H. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the AVR-S650H. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The TX-RZ820 supports the protection of digital content of the standard HDCP 2.2, versus HDCP 2.3 in the AVR-S650H. These compared receivers have 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 TX-RZ820 and AVR-S650H can be configured using the Setup assistant.
Only the TX-RZ820 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-RZ820.