Having had an opportunity to test Pioneer SC-LX901 vs Onkyo TX-NR545, 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 7.2, 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-NR545 has a power of 100/6. A common feature for devices is the same total harmonic distortion - 0.08%.
The manufacturer installed different DACs, the SC-LX901 received the model ESS SABRE32 Ultra 192 KHz/32-bit, but the TX-NR545 is equipped with Hi-Grade 384 KHz/32-bit. Each of the compared opponents supports Bi-amping. Both Pioneer SC-LX901 and Onkyo TX-NR545 can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
These units have the same Wi-Fi modules. Each of the receivers has a Bluetooth connector. Both devices can work with such Apple Music services: AirPlay. Access to the Spotify service is on each of the competitors. The number of available streaming services varies for receivers, the Pioneer SC-LX901 works with Deezer, TIDAL, Pandora, TuneIn Radio, but the Onkyo TX-NR545 works with Tunein Radio.
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-NR545. 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-NR545 has 6/1. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the SC-LX901 and the TX-NR545. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. SC-LX901 and TX-NR545 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.
Unlike the SC-LX901 where 3 Multi zones is provided, the TX-NR545 works with 2 Multi zones. 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 and the Onkyo TX-NR545 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available both models. Only in the SC-LX901 realized a DTS:X surround technology.