There are many things in the world that are impossible. Dividing by zero, bumblebees flying and the advertised price of sofas during the Bank Holiday sales are the usual examples. You can now add Onkyo's TX-SR605 to the list. Put it this way, for less than 400 of your hard earned pound notes, this receiver simply cannot exist.

But I have bitten it and it's absolutely real. I have also taken the lid off and guestimated the cost of all the sexy processing components.

To this figure I added a few shekels for the analogue bits and generic hardware, put on rough manufacturer and retailer margins, factored in the cost of customer service and support, etc - and came up with what I thought was a sensible price. It was between £600 - £700.

But here sits the Onkyo TX-SR605, with a 400 quid price point. Miracles happen. Even before it's switched the Onkyo on, I can safely say that no other budget receiver gets close in terms of features or technology.

Fully loaded

The top-line specs are pure eye-candy and designed to get even lay-home cinema enthusiast drooling. Top of the 'must have' list is a full HDMI v1.3a implementation, allowing DeepColor picture enhancing technology and decoding for Dolby True HD, Dolby Digital Plus and DTS HD Master Audio, but you'll have to wait for an HD player capable of outputting bitstream HD audio over HDMI.

The baseline figures are super-model territory; the TX-SR605 claiming seven channels of 140W with the option to bi-amp the front channels or go powered multi-room if you are happy with 5.1 channel in the main room.

There are neat 192 kHz/24bit DACs for all channels and a healthy selection of inputs. Okay, there are only two HDMI inputs, no pre-amp outputs and no 12V triggers - but the rest of the spec sheet more than makes up for it.

Operationally, the TX-SR605 is a dream to use. The setup is fully automatic and the system comes with basic Audyssey Room EQ. There is also a snazzy full-colour GUI which eclipses the blocky text menus of other similarly-priced receivers.

On the video side you get full HDMI up-conversion for every video input, albeit simply de-interlaced rather than upscaled to HD resolution. Not only does this simplify receiver to TV connection, it still does a fine job of improving picture quality from your old analogue sources too. There's also a full RI-control system for multiroom or integration with, say, Onkyo's RI iPod dock.

Clean bill

It would have been easy for Onkyo to cut corners internally to achieve this price point at the expense of quality of course - but if the sound is anything to go by, it certainly haven't. This receiver is clean and crisp and immaculately detailed with both Dolby and DTS movies alike.

Not the all-action monster I perhaps suspected, but a tense and cool-sounding performer that lusts after complex, emotionally taut scenes to wring every last nerve-straining moment from the soundtrack.

Stick on a moody classic like House of Flying Daggers and the TX-SR605 is in its element, eking out details and effect with samurai-like precision. The dialogue is forward in the mix and projects well into the room and bass effects are tighter than a spandex cat suit.

Dramas like The Painted Veil are not my personal cup of tea (the missus insisted...) but the Onkyo turns in a sterling performance, creating a grand impression of the scale of the sweeping scenery and keeping the dialogue intense.

300 on HD DVD is more my style, and the film is utterly gripping from start to finish as the Onkyo creates an intense and sometimes eerie atmosphere that few budget receivers even get close too.

The tension builds and by halfway through the movie sweat will be beading on your brow and palms.... largely because the TX-SR605's case gets hotter than a Dutch porn channel.

However, when the screen is full of clashing swords, blood-soaked leather and beards you could lose badgers in, the Onkyo does begin to reveal some of its shortcomings.

Bass effects never really get into 'thunderous' territory and with all channels driven hard the sound can head towards an acerbic ear-syringing if you have even remotely frisky speakers. I do feel guilty giving the TX-SR605 a dig for lack of ultimate grunt though. At £400 the only receivers that eclipse it for sheer drive do so at the expense of subtlety, features, advanced technology, future-proofing, classy GUIs and usability.

So, do I give a flying duck about why the TX-SR605 costs only £400? No! As long as the current price remains unchanged and Onkyo doesn't suffer a mysterious stock shortage, this receiver will remain the definitive budget best buy for ages.