The Denon AVR-S640H vs Yamaha RX-V581 comparison will be extremely helpful for people who want to get a great, powerful receiver with many functions.
The number of channels for receivers is different - 5.2 versus 7.2, respectively, for devices. In terms of power, there are differences, the AVR-S640H has such a ratio W/Ohm - 75/8, 100/6, while the RX-V581 has a power of 115/6. The value of total harmonic distortion is also different, and for the AVR-S640H it is 0.08%, but for the RX-V581 it is 0.09%.
The manufacturer installed different DACs, the AVR-S640H received the model 192 KHz/32-bit, but the RX-V581 is equipped with Burr-Brown 192 KHz/24-bit. The Bi-amping function is implemented only in the Yamaha RX-V581. Both Denon AVR-S640H and Yamaha RX-V581 can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Wireless Internet access via WIFI is possible on both units. Each of the receivers has a Bluetooth connector. The contenders have differences in the supported services from Apple - AirPlay, AirPlay 2 versus AirPlay respectively. Access to the Spotify service is on each of the competitors. The number of available streaming services varies for receivers, the Denon AVR-S640H works with Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, but the Yamaha RX-V581 works with Pandora, JUKE.
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 AVR-S640H and the RX-V581. None of the devices can increase the resolution of the incoming video signal. Operation with the Dolby Vision is only possible with the AVR-S640H.
The number of HDMI inputs/outputs varies depending on the receiver, the AVR-S640H has 5/1, and the RX-V581 has 4/1. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the AVR-S640H and the RX-V581. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. AVR-S640H and RX-V581 support the standard HDCP 2.2. In the presence of a built-in phono stage for connecting a vinyl player only at Denon AVR-S640H. There is an ECO mode in either AV receiver. The Denon AVR-S640H and the Yamaha RX-V581 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available only in the RX-V581. Only in the RX-V581 realized a DTS:X surround technology.