An affordable AV receiver is always a good option to consider, so Sony STR DH550 vs Pioneer VSX-S520 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Sony STR DH550 has 5.2 versus 5.1 for Pioneer VSX-S520. Regarding power, then STR DH550 has such a W/Ohm ratio - 90/6 when VSX-S520 has a power of 50/4. The THD is the same and is 0.09%.
Competitors' digital to analog converter (DAC) is identical to 192 KHz/24-bit. None of the models support Bi-amping. The Pioneer VSX-S520 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Only the VSX-S520 has Bluetooth support. Only the VSX-S520 supports Spotify.
Only the Pioneer VSX-S520 has support for High dynamic range (HDR). Only the VSX-S520 provides HDMI signal transmission in standby mode. The VSX-S520 can scale the input HDMI signal, unlike the STR DH550. Dolby Vision technology found support only on the VSX-S520.
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. The VSX-S520 has 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. The setup assistant will help you configure Pioneer VSX-S520.
Only the VSX-S520 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the VSX-S520.