An affordable AV receiver is always a good option to consider, so Onkyo TX-NR575 vs Pioneer VSX-S520 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Onkyo TX-NR575 has 7.2 versus 5.1 for Pioneer VSX-S520. Regarding power, then TX-NR575 has such a W/Ohm ratio - 135/6 when VSX-S520 has a power of 50/4. The THD is 0.08% for the TX-NR575 but 0.09% for the VSX-S520.
Characteristics of digital to analog converter (DAC) are different, 384 KHz/32-bit for TX-NR575 and 192 KHz/24-bit for the VSX-S520. Only the TX-NR575 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 Onkyo TX-NR575 has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Spotify can be used on each receiver. The TX-NR575 can work with the audio stream from Deezer, TIDAL, Pandora, TuneIn Radio, and the VSX-S520 can receive a content from Deezer, TIDAL, TuneIn Radio. 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-S520 can scale the input HDMI signal, unlike the TX-NR575. The HDR standard - Dolby Vision is supported by these receivers.
Each receiver has 4/1 HDMI inputs/outputs. 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 not present in each of the AV receivers. Both TX-NR575 and VSX-S520 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.