Having had an opportunity to test Onkyo TX-NR656 vs Onkyo TX-NR545, I’d like to share my impression here to facilitate your choice of a new AV receiver.
AV receivers under review have the same number of channels. In terms of power, there are differences, the TX-NR656 has such a ratio W/Ohm - 160/6, while the TX-NR545 has a power of 100/6. A common feature for devices is the same total harmonic distortion - 0.08%.
Competitive models use the same DAC. Each of the compared opponents supports Bi-amping. Both Onkyo TX-NR656 and Onkyo TX-NR545 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. 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 Onkyo TX-NR656 works with Deezer, 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 TX-NR656 and the TX-NR545. Video scaling is only possible with the TX-NR656. Review participants do not have the Dolby Vision feature.
The number of HDMI inputs/outputs varies depending on the receiver, the TX-NR656 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 TX-NR656 and the TX-NR545. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. TX-NR656 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 Onkyo TX-NR656.
Ability to create 2 Multi zones inherent in both AV receivers. 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 Onkyo TX-NR656 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 TX-NR656 realized a DTS:X surround technology.