The Onkyo TX-SR383 vs Pioneer VSX-LX503 comparison proves that these receivers have many common features.
A significant difference between the receivers in the number of channels, Onkyo TX-SR383 has 7.2 versus 9.2 for Pioneer VSX-LX503. Regarding power, then TX-SR383 has such a W/Ohm ratio - 100/8, 135/6 when VSX-LX503 has a power of 120/8, 230/6. The THD is 0.09% for the TX-SR383 but 0.08% for the VSX-LX503.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for TX-SR383 and AK4458 384 KHz/32-bit for the VSX-LX503. Only the VSX-LX503 supports Bi-amping feature. The Pioneer VSX-LX503 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Rivals from our review have Bluetooth support. Only the VSX-LX503 supports Spotify. 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-SR383. Dolby Vision technology found support only on the VSX-LX503.
The Onkyo TX-SR383 has 4/1 HDMI inputs/outputs versus 7/2 HDMI connectors of the Pioneer VSX-LX503. 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-LX503 has a built-in phono stage for connecting a vinyl player.
The TX-SR383 supports 2 Multi-room zones, versus 3 for the VSX-LX503. An ECO mode is not present in each of the AV receivers. The setup assistant will help you configure Pioneer VSX-LX503.
Only the VSX-LX503 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the VSX-LX503.