It makes sense comparing Yamaha RX-V581 vs Yamaha RX-V683BL because they both are able to give some premium features.
Considered AV receivers have the same number of channels 7.2. Regarding power, then RX-V581 has such a W/Ohm ratio - 115/6 when RX-V683BL has a power of 90/8, 150/4. The THD is 0.09% for the RX-V581 but 0.06% for the RX-V683BL.
Competitors' digital to analog converter (DAC) is identical to Burr-Brown 192 KHz/24-bit. Both the RX-V581 and the RX-V683BL support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Both models have the ability to connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay. Spotify can be used on each receiver. The RX-V581 can work with the audio stream from Pandora, JUKE, and the RX-V683BL can receive a content from Pandora, Sirius XM, Napster, JUKE, Qobuz. 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. The RX-V683BL can scale the input HDMI signal, unlike the RX-V581. Dolby Vision technology found support only on the RX-V683BL.
The Yamaha RX-V581 has 4/1 HDMI inputs/outputs versus 6/1 HDMI connectors of the Yamaha RX-V683BL. 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. The RX-V683BL has a built-in phono stage for connecting a vinyl player.
Each of the AV receivers from our review supports 2 Multi-room zones. A voice control is not available. It is also worth noting that the ECO mode is presented in each of the receivers. Both RX-V581 and RX-V683BL 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.