The Onkyo TX-RZ840 vs Pioneer VSX-LX503 comparison proves that these receivers have many common features.
Considered AV receivers have the same number of channels 9.2. Regarding power, then TX-RZ840 has such a W/Ohm ratio - 180/6 when VSX-LX503 has a power of 120/8, 230/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, AKM 384 KHz/32-bit for TX-RZ840 and AK4458 384 KHz/32-bit for the VSX-LX503. Both the TX-RZ840 and the VSX-LX503 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 Onkyo TX-RZ840 has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Spotify can be used on each receiver. Deezer, TIDAL, Pandora, TuneIn Radio - all of these streaming services have found application in each of the models.
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. The VSX-LX503 can scale the input HDMI signal, unlike the TX-RZ840. The HDR standard - Dolby Vision is supported by these receivers.
Each receiver has 7/2 HDMI inputs/outputs. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the TX-RZ840. 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.
Each of the AV receivers from our review supports 3 Multi-room zones. Supported voice control technologies are identical - Google Assistant. An ECO mode is not present in each of the AV receivers. Both TX-RZ840 and VSX-LX503 can be configured using the Setup assistant.
Both devices have support for Dolby Atmos multichannel audio format. The surround sound technology DTS:X is supported by devices under review.