Denon AVR-S640H has 5 channel amplifier and delivers 75 W (8 Ω, 20 Hz - 20 kHz, 2 channel driven) and also has a stable performance at 4 Ω load.
The Receiver has 4K passthrough up to 60p. It can bypass HDR10, Dolby Vision.
High-dynamic-range (HDR) video has greater dynamic range than standard-dynamic-range (SDR) video with brigter whites and deeper blacks. HDR10 was announced on August 27, 2015, by the Consumer Technology Association and uses the wide-gamut Rec. 2020 color space. It sends static metadata via video stream to the TV which calibrates its screen brightness and color according to that. HDR10 supports up to 1000 nits of brightness and 10-bit color which corresponds to 1024 shades of the primary RGB colors.
Dolby Vision is an update to HDR10 by adding dynamic metadata that can be used to more accurately adjust brightness levels up to 10,000 nits maximum brightness on a scene-by-scene or frame-by-frame basis and supports up to 12-bit color depth (4096 shades of RGB) and 8K resolution.
Denon AVR-S640H comes with Audyssey Dynamic EQ and Audyssey Dynamic Volume.
Audyssey Dynamic EQ selects the best possible frequency response and surround volume levels moment-by-moment. This ensures that the bass response, tonal balance and surround impression remain constant despite changes in volume. This is the first technology that carefully combines information from incoming source levels with actual output sound levels in the room, a pre-requisite for delivering a dynamic volume solution.
Your Listening experience can be greatly diminished when there are significant shifts in volume between television programs, commercials and within the program material itself. When this happens you must constantly adjust the volume to maintain your desired listening level. Audyssey Dynamic Volume monitors the volume of program material moment-by-moment and automatically adjusts it, maintaining the desired listening level for all content while optimizing the dynamic range to preserve impact.
Denon AVR-S640H comes with[y] Audyssey MultEQ room correction system and includes the calibration microphone.
Audyssey is an acoustic measurement technology which automatically restores the acoustic distortion caused by the acoustic behaviour of a room with only a push on a button. Audyssey equalization provides an clear, accurate, natural sound with voices and dialog that become focused and intelligible, restoring the musical balance. Musical instruments and sound effects become precisely localized and the surround soundstage is made seamless and enveloping.
Denon AVR-S640H can be connected to internet using ethernet cable or built-in wi-fi adapter. It can also connect to bluetooth devices via built-in bluetooth adapter. The Receiver works with Amazon Alexa and supports[y] AirPlay 2. It has 5 HDMI inputs and HDCP 2.2 copy protection. There is a phono input with built-in phono stage for connecting the cartridge output of the turntable directly to the Receiver.
Front panel has USB input.