Review of Denon AVR-S640H versus Onkyo TX-RZ840 will reveal the best features offered by the devices. According to the results of our review, Denon AVR-S640H received 6.2 points out of 10 possible, and Onkyo TX-RZ840 was rated 8.4 points. The release date of AVR-S640H is 2018, and TX-RZ840 is 2019. TX-RZ840 is better suited for home theater use than the AVR-S640H. Its sound profile is better balanced.
For the built-in amplifier, the devices received different marks - 6 and 8, respectively, on a 10-point scale.
The number of channels is equal to the number of possible connected speakers. The Denon AVR-S640H supports 5.2-channels sound, but Onkyo TX-RZ840 supports a 9.2-channels configuration.
RMS stands for the actual power of the receiver. The higher this value, the louder the sound can be produced. The differences between the models in terms of RMS power are significant - for the TX-RZ840 this value is 180/6 W/Ohm, and for the AVR-S640H it is 100/6 W/Ohm.
|Stereo power (RMS), W/Ohm||75/8, 100/6||180/6|
|Output impedance, Ohm||8, 6||6|
|THD in stereo, %||0.08||0.08|
After reviewing the audio features of each model, we can rate the AVR-S640H 6 out of 10, and the TX-RZ840 - 9.
Bi-amping is the amplification of one speaker with two amplifiers. This amplification method has a positive effect on sound quality. Bi-amping is possible on the TX-RZ840.
Most receivers now come with a microphone included. It is with the help of this microphone that the auto-calibration system functions, which adjusts the sound of the receiver to the room.
|Digital to analog converter (DAC)||192 KHz/32-bit||AKM 384 KHz/32-bit|
|Pure direct (straight)||✔||✔|
|Auto speaker calibration||Audyssey MultEQ||AccuEQ|
|Speaker A/B switching||✖||✖|
|Other audio features||Audyssey Dynamic Volume, Audyssey Dynamic EQ, Compressed Audio Restorer, Hi-Res audio||Advanced Music Optimizer, Theater-Dimensional, Hi-Res audio|
The connectivity of competitors in our comparison is markedly different, Denon AVR-S640H scored 7, and Onkyo TX-RZ840 scored 8 out of 10.
Bluetooth connection is now one of the main communication protocols for the receiver's control or even music broadcasting.
|USB||1 (USB 2.0)||1 (USB 2.0)|
Now music streaming services are gaining more and more popularity. They allow users to listen to millions of songs by subscription.
|Apple Music (AirPlay)||AirPlay, AirPlay 2||AirPlay, AirPlay 2|
|Other streaming services||Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud||Deezer, TIDAL, Pandora, TuneIn Radio|
The presence of many connectors makes the receiver more versatile. But there are also narrowly targeted models, the number of connectors which are limited to a certain area of use. And when choosing their own receiver, users need to consider exactly your goals for using the receiver. For extensive connection, Denon AVR-S640H got 6 points, but Onkyo TX-RZ840 received 8 points.
Denon AVR-S640H is equipped with 5/1 HDMI inputs and outputs, and Onkyo TX-RZ840 has 7/2 HDMI inputs and outputs.
HDMI eARC is the next step in the development of audio return channel technology, which works in conjunction with HDMI 2.1. Using eARC provides the highest sound quality for home audio systems. HDMI eARC is available on Onkyo TX-RZ840.
|HDMI ARC (Audio Return Channel)||✔||✔|
|HDMI eARC (Enhanced Audio Return Channel)||✖||✔|
|Digital content protection (HDCP)||HDCP 2.2||HDCP 2.2|
|Subwoofer output (LFE)||2||2|
|Headphone output||1 x 6.3||1 x 6.3|
|Optical digital input||2||1|
|Coaxial digital input||1||1|
|Phono (MM) input||✔||✔|
|Front panel connectors||USB, phones, setup mic||HDMI, phones, setup mic|
|Multi channel preamp output||✖||✔|
The AV receiver is the heart of the home theater. And in this case, support for all current video formats ensures the best user experience, so it is very important to consider this when choosing a device. Video features of the AVR-S640H were rated 6 out of 10 against the 8 for the TX-RZ840.
|HDR (High Dynamic Range)||✔||HDR10|
|4K signal pass-through||4K/60Hz||4K/60Hz|
|8K signal pass-through||✖||✖|
|HDMI signal pass-through||✔||✔|
|3D signal pass-through||✔||✔|
|HDMI pass-through in standby mode||✔||✔|
|Video conversion||✖||analog to HDMI|
|Analog to HDMI scaling||✖||✖|
|HDMI to HDMI scaling||✖||✖|
|Other video features||BT.2020, HLG||DeepColor, x.v.Color, HLG, BT.2020|
In terms of evaluating additional features, the AVR-S640H got 10 points, but the TX-RZ840 has 9.
Only the Denon AVR-S640H has the ECO mode.
|Voice control||Amazon Alexa, Google Assistant, Siri, Josh.AI||Google Assistant|
|App control||iPhone, iPad, iPod, Android||iPhone, iPad, iPod, Android|
|Tuner||AM, FM||AM, FM|
|Auto power off||✔||✔|
|Graphical user interface (GUI)||✔||✔|
|Firmware update||network, USB||network, USB|
|Other additional features||IP Control, Web Control||IP Control|
As the center of a home media system, each multichannel receiver has an additional set of terminals for connecting the second set of speakers to create additional audio space in Zone 2 or even Zone 3 where audio can have the separate source.
|Multi-room zones||has not||3|
|Zone audio output||has not||speaker, preout|
|Zone HDMI output||has not||✔|
|Multi-room control||has not||FlareConnect|
|Remote control input/output (IR)||0/0||1/0|
|DC trigger output (12V)||0||1|
Denon AVR-S640H got 5 points for the multichannel surround sound and Onkyo TX-RZ840 got 8.
Dolby Atmos' particularity is that this is the object-oriented sound format, that is, each audio signal object is independently sounded and connected to its spatial position. Onkyo TX-RZ840 can create 3D sound due to the Dolby Atmos support.
DTS:X is an algorithm used by the processor to create sound scenes, where sounds connected directly to objects rather than channels, and to determine the optimum sound output distribution in space. Surround sound with DTS:X is available on the TX-RZ840.
IMAX Enhanced is a licensing and certification program under which home theater devices deliver crisp 4K HDR pictures and powerful sound as it was designed by the IMAX engineers. The TX-RZ840 licensed by IMAX.
|Dolby (other)||Dolby Digital Plus, Dolby Pro Logic||Dolby Digital Plus, Dolby Atmos Height Virtualization|
|DTS HD Master||✔||✔|
|DTS (other)||DTS 96/24, DTS-HD, DTS-EXPRESS, DTS-Surround, DTS Neo:6||DTS-ES, DTS 96/24, DTS-HD, DTS-EXPRESS|