Having had an opportunity to test Yamaha RX-V671 vs Pioneer Elite SC-LX904, 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 - 7.1 versus 11.2, respectively, for devices. In terms of power, there are differences, the RX-V671 has such a ratio W/Ohm - 90/8, 150/4, while the Elite SC-LX904 has a power of 140/8. The value of total harmonic distortion is also different, and for the RX-V671 it is 0.09%, but for the Elite SC-LX904 it is 0.08%.
The manufacturer installed different DACs, the RX-V671 received the model Burr-Brown 192 KHz/24-bit, but the Elite SC-LX904 is equipped with ES9026PRO 384 KHz/32-bit. Each of the compared opponents supports Bi-amping. Both Yamaha RX-V671 and Pioneer Elite SC-LX904 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Each of the receivers has a Bluetooth connector. The Elite SC-LX904 has access to the Spotify service. The number of available streaming services varies for receivers, the Yamaha RX-V671 works with Napster, but the Pioneer Elite SC-LX904 works with Deezer, TIDAL, Pandora. 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 RX-V671 and the Elite SC-LX904. Each of the devices can increase the resolution of the incoming video signal. Operation with the Dolby Vision is only possible with the Elite SC-LX904.
The number of HDMI inputs/outputs varies depending on the receiver, the RX-V671 has 6/1, and the Elite SC-LX904 has 7/3. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is only supported by the Elite SC-LX904. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. The RX-V671 has support for the standard HDCP 2.2, compared to the Elite SC-LX904, which supports the standard HDCP 2.3. Like most receivers, our models have a built-in phono stage for connecting a vinyl player.
Unlike the RX-V671 where 2 Multi zones is provided, the Elite SC-LX904 works with 3 Multi zones. There is an ECO mode in neither AV receiver. The Pioneer Elite SC-LX904 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available only in the Elite SC-LX904. Only in the Elite SC-LX904 realized a DTS:X surround technology.