It makes sense comparing Denon AVR-S640H vs Integra DTM-6 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Denon AVR-S640H has 5.2 versus 2.0 for Integra DTM-6. Regarding power, then AVR-S640H has such a W/Ohm ratio - 75/8, 100/6 when DTM-6 has a power of 80/8. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/32-bit for AVR-S640H and AK4438 384 KHz/32-bit for the DTM-6. None of the models support Bi-amping. The Denon AVR-S640H can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Rivals from our review have Bluetooth support. The Denon AVR-S640H has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Spotify can be used on each receiver. The AVR-S640H can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, and the DTM-6 can receive a content from Deezer, TIDAL, Pandora, TuneIn Radio.
Only the Denon AVR-S640H has support for High dynamic range (HDR). Only the AVR-S640H provides HDMI signal transmission in standby mode. Both competitors are not able to scale the HDMI signal. Dolby Vision technology found support only on the AVR-S640H. Only the AVR-S640H supports HDMI Audio Return Channel (ARC). Unfortunately, HDMI eARC is not available on monitored devices. Of the two receivers in our comparison, HDMI CEC is present in only the AVR-S640H. These compared receivers have a built-in phono stage for connecting a vinyl player. The AVR-S640H supports voice control via Amazon Alexa, Google Assistant, Siri, Josh.AI, and the DTM-6 - Google Assistant. An ECO mode is only available for the AVR-S640H. The setup assistant will help you configure Denon AVR-S640H.
None of the rivals equipped with Dolby Atmos multichannel audio decoder. The receivers do not support the surround sound technology DTS:X.