Onkyo TX-NR906

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Onkyo TX-NR906

From Hi-Fi World - March 2009 issue

Yo Smoothie!


Unlike your average AV receiver, Onkyo's new TX-NR906 is blessed with a surprisingly benign and listenable sound - plus every feature bar the kitchen sink, of course. Noel Keywood welcomes it in to his world...


It's unlovely, as big as a cruise ship and aims to satisfy your every need - especially if you are an audiophile, because this monster seemingly has proper SACD convertors onboard. So it should give superb sound from SACD, as well as Blu-ray. Oh, and it even caters for LP. So is Onkyo's new TX-NR906 receiver an audiophile dream?


The TX-NR906 is certainly tilted toward audio, but not for the reasons you might expect. As a fully specified top-of-the-range receiver not only can it do the fandango if you find the right menu, but Onkyo have fitted something that opens up a whole new level of complexity, as well as angst - well, that's how I see it. It has an internet connection! More frightening, it is Microsoft certified as PlaysForSure with Windows (er - can anything do that?). So, being MacIntosh equipped and Vista encumbered I knew I was in for fun with this Onkyo...


To be specific it will play music files from your computer, in MP3, WMA, WAV and AAC form. Onkyo say it is compatible with Windows Media Player; there's no mention of anything else, especially with an 'i' prefix like - dare I mention it - iTunes. It will also play internet radio through the surround system. All in all then, this is one very capable receiver that can handle audio in all its many forms, seemingly PC based only. I put it on my network with PCs and Macs to see how it fared.


All this ability doesn't come for nothing;  AV receivers are hideously complicated boxes tricks, this one more so than usual. Onkyo pack a set of handbooks almost the size of Encyclopedia Britannica.


The TX-NR906 inevitably delivers a mighty wallop through seven amplifying channels. Delivering 220 Watts per channel to 7 channels according to a front panel sticker and we measured 290 Watts. To avoid confusion I must explain that the sticker value of 220 Watts is into 6 Ohms, and as we measured 153 Watts into a 8 Ohms and 290 Watts into 4 Ohms the sticker value is correct. Onkyo's power supply really does perform, the TX-NR906 being able to sink 2kW into seven loudspeakers!


A neat line of loudspeaker outlets able to accept 4mm plugs runs across the bottom of the rear panel and Onkyo provide colour coding, making hook up as easy as it can get when you are grappling with more cables than they have in Broadcasting House. If you don't want to use Rear loudspeakers you can use the spare amplifying channels for other rooms, or for bi-amping the front loudspeakers to improve quality, or bridged to double power output. For quality music reproduction in the average lounge the front centre loudspeaker can be eliminated too. The spare rear channels can then be used to bi-amp the front loudspeakers for improved quality. All modern receivers allow this, manufacturers becoming aware that full-on 7.1 is often impractical.


As expected the TX-NR906 decodes all coded music formats from DTS and Dolby, including the most processor intensive DTS HD Master Audio. It also has Pro Logic IIX, DTS Neo 6 and THX Neural Surround to turn stereo into surround-sound.


As you'd expect in a serious audio receiver, 24/192 digital-to-analogue convertors are used on all channels, so you get full bandwidth out to 96kHz in theory from top quality 192kHz (data rate) digital sources on DVD-A and Blu-ray. Our measurements showed you get it in practice too, not some compromise figure. Onkyo are diligent about things like this I'm coming to learn from testing their products, whilst rivals are not. You also get full bandwidth from 44.1 code on CD and 24/96 on DVD and Blu-ray.


The picture got even better with DSD processing from SACD, but only when in DSD Direct mode which gives full SACD bandwidth; otherwise a low bandwidth limit of 20kHz is applied. I realised there was a transposition error on p106 of the handbook here, 'Yes' meaning DSD signals are not processed by the DSP; Onkyo told me they will correct this.


Distortion levels were low all round so this receiver is able to convey the benefits of 24bit PCM and DSD through proper DSD convertors, even if it cannot rival a dedicated SACD player.  The Onkyo is 'serious'; it doesn't offer something then do it badly.


Digital sources can be connected via three HDMI inputs, or through optical and electrical S/PDIF inputs. There are of course normal phono socket analogue inputs, including one for turntables fitted with an MM cartridge and it measured well.


Being a receiver, a VHF/FM and Medium Wave AM tuner are fitted, but not DAB. Thousands of internet radio stations from around the world are available too. These come in as low data rate (i.e. highly compressed) digital streams so you don't get great quality, but it isn't far off DAB. As always VHF/FM offers best sound quality and the tuner fitted is a good one, our measurements showed. To appreciate this an external aerial is required, because like all VHF tuners this one needed a strong signal from the aerial to minimise hiss and you won't get that from an indoor aerial unless you live close to a transmitter. Station frequencies can be entered from the remote, but committed to memory only at the receiver itself.


So audio wise the TX-NR906 looks strong. It works with every source, analogue and digital from LP through to Blu-ray (phew!) and offers great results from all of them. However, whilst it has a 7.1 preamp output, it does not have a multichannel input, so you cannot connect legacy DVD or SACD players using analogue cables!


But I haven't mentioned computer files and the enormous fun (not!) I had sorting through this receiver's NET/USB function, or should I say two of them, which is confusing. The handbook says on p123 press Net/USB in steps 2 and 3, but one is Net/USB Input, the other Remote Control mode, a point I missed which caused me some initial confusion. A lot of switching between the two is needed to get internet radio stations running and it is best to use a TV for visual guidance. Station name, URL, data rate, digital resolution and compression scheme are all displayed, useful when selecting for quality. Unfortunately, a station isn't retained at switch off, as with VHF/FM; the Onkyo reverts to the first station in a list of twenty at switch on.


Because Onkyo load the receiver with vTuner (see in this position around 10,000 stations buried in folders and subfolders exist here - a bewildering array sorted by music, geographical location, etc. The other nineteen positions are easily loaded with station URLs gleaned from sites found by computer, like or Apple's free iTunes player which usefully reveals URLs from an INFO request. If you erase vTuner by accident as I did, a receiver reset restores it. Radio station names and URLs can be loaded by a web browser and both Mac (Safari) and PC (Explorer) located the Onkyo on my internal network and did this.



Talking of which, plugging the TX-NR906 into a Netgear router via ethernet brought it up on the client list immediately, without problem using DHCP. The Onkyo would see PCs running both Windows XP and Vista as a server, connecting successfully to them and playing stored music files; it would not see an iTunes player on PC however which, being a closed player, was as expected.


Whilst Macs could see the Onkyo's web page, the Onkyo was unable to identify them as music servers, as expected. Onkyo do specify only a PC running Windows XP as a minimum requirement and Windows Media 11 player (free download) as compatible in the handbook. Sharing must be turned on at the computer and both Firewall and Antivirus either turned off or set to allow communication; Kaspersky on my Vista PC completely blocked communication.


Apart from the inevitable foibles of networking the Onkyo was sort of easy to use. I guessed immediately that a blank screen at start up was due to the HDMI output not being sent the video signal, something that must be fixed using the on-receiver display before the setup menus can be accessed. This is going to cause new owners grief I am sure; a blank screen at start up is bewildering.


There is an Audyssey MultEQ XT automatic loudspeaker set-up system and linked Dynamic EQ system. You can see and manually trim its results, and there is a 7 band equaliser on each channel. Unfortunately, this isn't able to trim low frequency room modes. Full THX certification exists with a wide range of functions.


Video wise an HQV-Reon processor provides upscaling of SD video from DVD if you have a DVD that cannot do this internally. Composite, Component and S-Video signals can be transcoded and upconverted to digital, output via HDMI.


The TX-NR906 worked smoothly enough, only delivering spits and pops on occasion when switching furiously as I am sometimes want to do to, between disc menu and play, and selecting Direct and Pure Direct modes.


Moving to the big Onkyo from a Marantz SR8002 brought forth the company's house sound, briefly described as fulsome at low frequencies, smooth across the midband and quite mild across the treble regions. Onkyo aim not to offend aurally and voice their products consistently to achieve this. The TX-NR906 was a very easy going listen as a result, with no hint of hardness, harshness, grit or tizz. Images were a little less clearly resolved than the Marantz, but conversely the Marantz sounded a little harder, even glassy in its tonality. I did notice some muddle if Pure Direct wasn't used, but I use this with the Marantz too.


The TX-NR906's big power supply truly does deliver a mighty wallop, plus an extra octave extension downward of low bass it seemed. The Wagnerian drum roll in the Overture of Within Temptation's 'Black Symphony' DVD (DTS 24/96) had deep rumbling power; I wondered whether somebody had re-routed the Bakerloo Line beneath Maison Keywood. Following drum rolls all had massive low frequency presence: the big Onkyo is a real ground shaker and spectacular if you like thunderous bass. I never faulted its clear, easy going midband nor clean treble, free from emphasis. Strings were smooth, tubas filled the lower octaves heartily and French horns sounded fruity in this latest spectacular from Within Temptation.


With SACD in 'DSD Direct' mode and the displays off for Pure Audio, strings in Beethoven's 'Eroica' Symphony No3 were surprisingly smooth and mild in nature, as they were in Rachmaninov's Piano Concerto No2, accompanying Lang Lang on piano.  The organ in Purcell's 'Rondeau from Abdelazar' shook my room and stood impressively apart from the wonderfully sonorous horns. In a nutshell then SACD reproduction was mild mannered but big hearted, the Onkyo again being clear but easy going, able to convey the extra smoothness and extended textural range of a DSD recording.



Spinning Santana's 'Put Your Lights On' in 24/96 PCM code from DVD-A again showed how smooth, yet powerful and atmospheric the Onkyo could be. Everlast's voice was gravelly, whilst Santana's guitar hovered easily in front of me, with solid attack behind plucked strings and an especially satisfying follow through of their harmonic content. The Onkyo paints a big picture that's generously textured but always easy on the ear, quite an unusual combination.


VHF/FM radio has been tailored for a similar sonic and it too was plentiful in low frequency content, giving music weight and body, unlike so many VHF tuners that sound neutered. A live recording of a John Lennon cover of 'Jealous Guy' on Absolute FM (aka Virgin) was warmly atmospheric and had a lovely enveloping quality, the strings of a strummed guitar sounding sweet and sonorous. Stepping down through London's stations showed they all came in sounding clean and easy, with a lovely midband in particular and none of the flat sound staging that is so common; I was reminded of my Leak Troughline, so it's a classy tuner for sure. As I said earlier, Onkyo don't cut corners and hope no one will notice, unlike others.


Spinning LP with an Ortofon 2M Black cartridge in an SME312 on Garrard 401 brought forth a full sound with weighty bass, a smooth midband and no treble sting. With a good turntable and cartridge the  Onkyo is no slouch with LP.



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