Onkyo TX-NR646 7.2-Channel Network AV Receiver

Model: TX-NR646 UPC: 751398012228 Item: 163963

Great sound is key when it comes to your home entertainment experience, and the Onkyo TX NR646 delivers the highest quality sound without compromise. Enjoy crystal clear 4K Ultra HD video content and decoding for Dolby Atmos and DTS:X, technology that will make your home entertainment more immersive and life-like. Plus, the built-in WiFi lets you access all of your favorite songs from a variety of streaming apps.

Onkyo TX-NR646 Receiver Features:

  • Experience captivating surround sound with Dolby Atmos and DTS:X
  • Endless music streaming options available with Bluetooth technology
  • Support for 4K Ultra HD allows you to enjoy crystal clear video content
  • Convenient playback and control through a free Onkyo mobile app

Product Information

Onkyo receivers are considered the industry standard by audio experts, and have a long track record of providing quality AV and stereo sound. The TX-NR646 Onkyo receiver is the latest torch-bearer, combining updated technologies such as 4K pass-through and Dolby Atmos compatibility, so your home theater continues to improve with each advancement.

This Onkyo network receiver has been hailed by CNET as a “powerful, feature-packed receiver,” with multi-functionality such as Bluetooth and AirPlay music streaming capabilities, DTS:X object-based surround sound, and built-in WiFi for easy-to-setup network connections. With 170 watts funneling through to each channel, the result is a clean, powerful sound.

Shop our custom designed TX-NR646 Home Theater Speaker Packages, designed by our product experts.


Onkyo TX-NR646 7.2-Channel A/V Receiver Highlights:

  • DTS:X Support
  • Dolby Atmos Support
  • 170 W per Channel
  • Hi-Current Amp Design for Authentic Sound Reproduction
  • HDMI 8 In / 2 Out Including 1 Front
  • HDMI & HDCP 2.2 for 4K UltraHD
  • Built-in Bluetooth & Wi-Fi with Pandora, Spotify, and AirPlay
  • DSD 5.6 MHz, FLAC 192 kHz/24-bit Hi-Res Audio Capable
  • 384 kHz/32-bit Hi-Grade DAC
  • AccuEQ Room Acoustic Calibration


Onkyo TX-NR646 7.2-Channel A/V Receiver Features:

DTS:X Compatible

  • DTS:X is a next-generation object-based surround sound technology that includes height to deliver a fully-immersive listening experience. DTS:X provides listeners the ultimate in flexibility, immersion, and interactivity. Unlike channel-based audio, you will be able to personalize your audio experience. For example, you can turn up JUST the dialog within a mix. DTS:X allows you to customize to your room layout as well as control dialog and dynamic range.

Supports Dolby Atmos Up to 5.1.2 Channels

  • With Dolby Atmos, sound comes alive from all directions, including overhead. The format combines a channel-based audio bed with object-oriented sound to place and move specific effects around the room, creating a breathtakingly realistic and captivating sonic atmosphere.
  • Sound designers and artists are free to mix in a 3D space, steering effects through surround channels and adding a seamless overhead dimension with discrete height channels.
  • Additionally, a new Dolby surround up-mixer allows for your current channel-based content (that has not been mixed for Dolby Atmos) to be expanded to fill the flexible speaker layouts of a Dolby Atmos system.

Hi-Current Amp Design for Authentic Sound Reproduction

  • From the quietest dialog passages to booming action scenes, Onkyo's exclusive amplification technology dramatically enhances the audio dynamics of your movies, music and games.
  • This Wide Range Amplifier Technology (WRAT) is at the core of Onkyo's signature sound. The innovative amplifier design is comprised of three key elements:
    • (1) a low negative feedback design for punchy, true-to-life sound, and cleaner audio across the frequency ranges;
    • (2) closed groundloop circuits to reduce individual circuit noise and keep the ground potential free of distortion; and
    • (3) a high instantaneous current to handle big dynamic gains.
  • This allows massive power at 170 W/Ch (6 Ohms, 1 kHz, 0.9% THD, 1 Channel Driven, FTC) and 100 W/Ch (8 Ohms, 20 Hz–20 kHz, 0.08% THD, 2 Channels Driven, FTC).

HDMI 8 In / 2 Out Including 1 Front (4K UltraHD / HDCP 2.2)

  • All HDMI terminals support 4K/60Hz, as well as HDCP 2.2 for next-generation UltraHD streaming and broadcasting.

Bluetooth Audio / Wi-Fi with Spotify and AirPlay

  • The TX-NR646 has AirPlay, Wi-Fi and Bluetooth technologies built in. The free Onkyo Remote app puts a range of streaming options at your fingertips, from universal hi-res audio via network-attached devices to internet streaming services to music on your smartphone and tablet. Or pair up and enjoy whatever's playing on your Bluetooth-compatible device for huge cinematic sound.
  • This receiver comes loaded with Spotify, Pandora, SiriusXM Internet Radio, Slacker and TuneIn. You can select a station and search for music available on these services via the Onkyo Remote app on your phone. You'll never be short of your favorite music to enjoy.

384 kHz/32-bit Hi-Grade DAC

  • No matter what you're listening to, it will sound powerfully full, clean and clear. A premium-quality AK4458 digital-to-analog converter from Asahi Kasei implements unique low-distortion filtering technologies for clear sound, and unlocks the full potential of any audio format, including compressed, lossless, and hi-res audio (MP3, WMA, WMA Lossless, FLAC, WAV, OggVorbis, AAC, Apple Lossless, DSD 5.6 MHz, LPCM, and Dolby TrueHD).

Classic Analog & Hi-Res Digital

  • This receiver is engineered for hi-res analog and digital audio. You can spin your classic vinyl and hear it in all its analog glory and stream your networked hi-res digital files. Both analog and digital audio sound its warmest and clearest. The TX-NR646 supports hi-res audio playback, gapless playback, and the ability to play DSD, Double DSD, FLAC and ALAC along with other Hi-Res formats.

Powered Zone 2 and Zone 2 Line-Outs

  • The TX-NR646 features Powered Zone 2 and Zone 2 line-outs. This lets you assign two channels to power audio in a room equipped with speakers. An existing hi-fi system in a third room can also be connected via the line-out, enabling the use of the A/V receiver as a pre-amp and audio server.


Onkyo TX-NR646 7.2-Channel A/V Receiver Advanced Specifications:


  • # Channels: 7.2
  • Power Watts/Ch (6 Ohms 1kHz, 1 Channel Driven, FTC): 170, 0.9% THD
  • Power Watts/Ch (8 Ohms 20-20kHz, 2 Channels Driven, FTC): 100, 0.08% THD
  • WRAT (Wide Range Amplifier Technology)
  • H.C.P.S (High Current Power Supply): Massive High Power Transformer
  • Continuous 6 Ohms Rated
  • Discrete Output Stage Circuitry
  • Independent Power Supply: x2
  • Bi-amp Capability For Front


  • Dolby Atmos
  • 32-Bit Digital Signal Processing Engine: Dual DSP for Powerful Advanced Processing
  • Dolby Decoder: Atmos, True HD, DD Plus
  • DTS:X
  • DTS Decoder: DTS:X, DTS-HD Master Audio
  • ONKYO GAME Surround Modes: Rock, Sports, Action, RPG
  • AccuEQ Room Calibration: Advanced
  • Phase-Matching Bass Boost: for Deep Bass and Clear Mid-Range
  • Pure Mode
  • Advanced Music Optimizer: Bluetooth Included
  • 384K/32 Bit DACs: AKM4458


  • Audio I/O: 7 / 0
  • Phono Input
  • Digital Audio IN (OPT/COAX): 2 / 1
  • Composite I/O: 3 / 0
  • Component Video I/O: 2 / 0
  • Front Panel HDMI
  • USB Input: Rear
  • HDMI I/O: 8 / 2
  • HDMI 4K/60 Hz- Capable HDMI Terminals: HDR Support
  • HDCP 2.2 Copy-Protection Compatibility: 3 in / 2 out
  • HDMI Support for High Dynamic Range
  • HDMI Support for 3D, Audio Return Channel and CEC
  • HDMI Support for Deep Color, x.v.Color, LipSync
  • HDMI Support for DVD-Audio, SACD, Multichannel PCM              
  • Analog To HDMI Upconversion: from 480i/576i
  • 4K Passthrough
  • Analog Pre-Outs: Subwoofer (x2)
  • Powered Zone 2
  • Zone 2 Line Out: Fixed
  • Zone 2 Digital to Analog Audio Conversion: S/PDIF, NET, USB
  • Made for iPod, iPhone, iPad
  • Airplay
  • Supports Onkyo Remote App: iPod touch/iPhone and Android-Powered Devices
  • Internet Radio Capable: Pandora, Spotify, Sirius, Slacker, Aupeo!, TuneIn
  • Spotify Connect Support
  • Streaming Audio From PC / Network: DLNA, Home Media
  • Hi-Res Streaming Audio Formats: Apple Lossless, DSD 2.8/5.6 MHz, Dolby TrueHD, FLAC 192/24, LPCM, Ogg Vorbis, WAV, WMA
  • Streaming Audio From USB memory
  • Wireless Network: Wi-Fi-Certified
  • Bluetooth: Built-in

Integration Access

  • Ethernet
  • ONKYO-RI System Control
  • RIHD (Remote Interactive Over HDMI)


  • Learning Remote
  • On Screen Remote Programming
  • Bi-directional Remote Setup via GUI
  • Hybrid Standby Function: to Reduce Power Consumption
  • Smart Grid-Ready
  • Auto Speaker Calibration W/Mic.: AccuEQ - Advanced
  • OSD Out: Advanced "Home" GUI
  • Warranty: 2 YEARS




Onkyo TX-NR646 7.2-Channel A/V Receiver Specifications:

Amplifier Section - Power Output

  • All Channels:
    • 170 W/Ch (6 Ohms, 1 kHz, 0.9% THD, 1 Channel Driven, FTC);
    • 100 W/Ch (8 Ohms, 20 Hz–20 kHz, 0.08% THD, 2 Channels Driven, FTC)
  • Dynamic Power:
    • 240 W (3 Ohms, Front)
    • 210 W (4 Ohms, Front)
    • 120 W (8 Ohms, Front)
  • THD+N (Total Harmonic Distortion + Noise): 0.08% (20 Hz-20 kHz, Half power)
  • Damping Factor: 60 (Front, 1 kHz, 8 Ohms)
  • Input Sensitivity and Impedance:
    • 200 mV/47 k-ohms (Line)
    • 5 mV/47 k-ohms (Phono MM)
  • Rated RCA Output Level and Impedance:
    • 100 mV/2.2 k-ohms (Zone 2 Line Out)
    • 200 mV/470 Ohms (Subwoofer Pre Out)
  • Maximum RCA Output Level and Impedance:
    • 0 V/2.2 k-ohms (Zone 2 Line Out)
    • 0 V/470 Ohms (Subwoofer Pre Out)
  • Phono Overload: 70 mV (MM, 1 kHz, 0.5%)
  • Frequency Response: 10 Hz-100 kHz/+1 dB, -3 dB (Direct Mode)
  • Tone Control:
    • +/ 10 dB, 20 Hz (Bass)
    • +/ 10 dB, 20 kHz (Treble)
  • Signal-to-Noise Ratio:
    • 100 dB (Line, IHF-A)
    • 80 dB (Phono MM, IHF-A)
  • Speaker Impedance: 6 Ohms–16 Ohms

Video Section - Input Sensitivity/Output Level and Impedance

  • Video:
    • 0 Vp-p/75 Ohms (Component)
    • 7 Vp-p/75 Ohms (Component PB/CB, PR/CR)
    • 0 Vp-p/75 Ohms (Composite)
  • Component Video Frequency Response: 5 Hz–13.5 MHz/+0 dB, -3dB

Tuner Section - Tuning Frequency Range

  • FM: 87.5 MHz–107.9 MHz
  • AM: 530 kHz–1,710 kHz
  • FM/AM Preset Memory : 40 stations


  • Power Supply: AC 120 V~, 60 Hz
  • Power Consumption: 6.4 A
  • No-Sound Power Consumption: 70 W
  • Standby Power Consumption: 0.1 W
  • Dimensions (W x H x D): 17 1/8" x 6 13/16" x 12 15/16" (435 x 173.5 x 329 mm)
  • Weight: 20.7 lbs (9.4 kg)


Reviews (1)


1 Reviews

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  1. 5.0 out of 5 stars

    Onkyo outshines again

    I've had many different receivers over the years and Onkyo always has the best features/price ratio. The 646 is no exception. It has a great full sound and supports all of the modern technology such as HDCP 2.2, HDMI 2.0 on most to all of its ports. This a rarity in this price range and needed for all of your 4K devices to work properly. It also supports Dolby Atmos and DTS-X which are the next generation sound formats. A few years ago I had spent a lot of money on the Harmon Kardon AVR2600 due to the reviews - but I was extremely underwhelmed by the receiver and the sound was not very good through my Bose Acoustimass 10 Series IV Home Entertainment Speaker System. Stick with the Onkyo and you will be happy.

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