It makes sense comparing Marantz NR1609 vs Onkyo TX-NR595 because they both are able to give some premium features.
Considered AV receivers have the same number of channels 7.2. Regarding power, then NR1609 has such a W/Ohm ratio - 50/8, 70/6 when TX-NR595 has a power of 80/8, 170/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for NR1609 and AKM 384 KHz/32-bit for the TX-NR595. Both the NR1609 and the TX-NR595 support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Rivals from our review have Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay, AirPlay 2. Spotify can be used on each receiver. The NR1609 can work with the audio stream from Deezer, Pandora, TuneIn Radio, and the TX-NR595 can receive a content from Deezer, TIDAL, Pandora, TuneIn Radio. 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. Both rivals can scale the resolution of the incoming HDMI signal. The HDR standard - Dolby Vision is supported by these receivers.
The Marantz NR1609 has 8/1 HDMI inputs/outputs versus 6/2 HDMI connectors of the Onkyo TX-NR595. 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. These compared receivers have a built-in phono stage for connecting a vinyl player.
Each of the AV receivers from our review supports 2 Multi-room zones. The NR1609 supports voice control via Amazon Alexa, Google Assistant, Siri, Josh.AI, and the TX-NR595 - Google Assistant. An ECO mode is only available for the NR1609. Both NR1609 and TX-NR595 can be configured using the Setup assistant.
Both devices have support for Dolby Atmos multichannel audio format. The surround sound technology DTS:X is supported by devices under review.