Having had an opportunity to test Pioneer SC-LX901 vs Onkyo TX-SR373, I’d like to share my impression here to facilitate your choice of a new AV receiver.
The number of channels for receivers is different - 11.2 versus 5.1, respectively, for devices. In terms of power, there are differences, the SC-LX901 has such a ratio W/Ohm - 140/8, 200/6, while the TX-SR373 has a power of 135/6. The value of total harmonic distortion is also different, and for the SC-LX901 it is 0.08%, but for the TX-SR373 it is 0.06%.
The manufacturer installed different DACs, the SC-LX901 received the model ESS SABRE32 Ultra 192 KHz/32-bit, but the TX-SR373 is equipped with 192 KHz/24-bit. The Bi-amping function is implemented only in the Pioneer SC-LX901. The model SC-LX901 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Each of the receivers has a Bluetooth connector. The SC-LX901 has access to the Spotify service.
Support for the HDR function can only boast of each of the AV receivers. The quality of 4K/60Hz signal remains unchanged when transmitting from a source to a TV or projector via HDMI for both receivers. Signaling over HDMI in standby mode can provide the SC-LX901 and the TX-SR373. Video scaling is only possible with the SC-LX901. Operation with the Dolby Vision is only possible with the SC-LX901.
The number of HDMI inputs/outputs varies depending on the receiver, the SC-LX901 has 8/2, and the TX-SR373 has 4/1. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the SC-LX901 and the TX-SR373. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. SC-LX901 and TX-SR373 support the standard HDCP 2.2. In the presence of a built-in phono stage for connecting a vinyl player only at Pioneer SC-LX901. Voice control of the basic functions of the receiver is not realized in both models. There is an ECO mode in neither AV receiver. The Pioneer SC-LX901 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available only in the SC-LX901. Only in the SC-LX901 realized a DTS:X surround technology.