Onkyo has revealed details of two more home cinema amplifiers for 2015, sitting above its previously announced budget machines, and priced at £549 and £849.

The 7.2-channel TX-NR646 (pictured, above) and TX-NR747 (below) amps will offer support for both Dolby Atmos and DTS:X, though support for DTS:X will come later in the year via a firmware update.

The two new home cinema amps follow in the footsteps of the entry-level TX-SR343 and TX-NR545

Onkyo is pushing the amps' support for next-gen surround sound formats, with DTS:X also incorporating Neural:X, which promises to use spatial mapping to bring a similarly all-encompassing sound to soundtracks encoded in other formats, such as DTS and PCM.

Each amp has eight 4K/60 Hz-ready HDMI 2.0a inputs and two multi-zone outputs, including HDCP 2.2-compliant terminals to support 4K streaming and even UltraHD Blu-ray discs, which are due later this year. High Dynamic Range (HDR) colour and 21:9 cinema-aspect are also supported.

MORE: HDR, Quantum Dot and Dolby Vision explained 

More after the break

Both the new Onkyo AV receivers support wireless streaming over Wi-Fi, AirPlay and Bluetooth, and integrate Spotify Connect. Onkyo’s Remote App 3 can also stream digital music stored on you mobile and brings access to various Internet radio and on-demand music services.

If high-res audio is your bag, then 192kbps/24-bit FLAC and DSD files are supported over DLNA, or you can ride the vinyl revival by plugging in a turntable via the phono input.

The TX-NR646 claims 160 watts of power per channel, while the TX-NR747 claims 175 watts and is THX Select 2 Plus certified. Both receivers are fitted with Dual 32-bit DSP Engines and a new 384 kHz/32-bit AK458 DAC.

Onkyo has also updated its AccuEQ room calibration with the aim of making the initial setup that much easier.

The new amps join home cinema amps from Denon and Marantz, which will also add DTS:X support to their existing Atmos spec later this year, albeit via a 199 euro hardware upgrade.

The Onkyo TX-NR646 will go on sale at the end of May, in black or silver, for £549. The TX-NR747 will be available in mid/end of June, in black or silver, for £849.

MORE: Best home cinema amps 2015


simonlewis's picture

No front USB socket, not the

No front USB socket, not the best of decisions imo.     Scratch one-s head

Jim May's picture

it looks like there is one

it looks like there is one next to the headphone jack on the bottom left

simonlewis's picture

It looked more like a HDMI

It looked more like a HDMI port to me and i have just checked onkyo's website and it is.

Geddy76's picture

Re: No front USB

You could just run a short extension from the rear USB port.  If the sound quality is good enough, I'd forgive that small drawback.

jazzanova's picture


"The TX-NR747 will be available in mid/end of June, in black or silver, for £849."


TX-NR747 is available right now at Amazon.

jleroy68's picture


In the UK or ? Everyone I'm finding says soon, but not yet. Please share the link of the stock ones.

mdc30's picture

Onkyo TX NR646

Hi I have just bought an upgrade to my old onkyo TX NR616 which i had many problems with. (manifacture problems)

Now i have Onkyo TX NR646 which reviews were amazing. Well i am not a super expert but has anyone noticed the noise of flowing current from the speakers when the AV-receiver is on without playing anything? Then if you pay attention even with the music a bit louder you can still hearing the same buzz. This is not a problem of unit as i have asked to replace it straight away as i though there was something wrong. Unfortunatelly the new unit does the same noise. Only when i disconnect the main HDMI cable from the cable box or from the main unit this stops.

Any thought or help on that? It looks like i will get rid of it asap to go Denon or Pioneer.

Any help is much appreciated.



Firebug's picture

Onkyo TX NR646

Maybe there is a distortion in your power supply of your tv? And with getting rid of that connection it stops? I would try to put another cable or tv or power supply made for Hi Fi. And see what happens.

Just an idea.