I often get an attack of deja-vu on the sofa, usually the result of too many days spent in a darkened room with nothing but cinema snacks for company. But I've definitely seen this Onkyo before...
In fact, not more than a couple of months ago the Onkyo TX-SR674E hit the test bench and came up trumps for value. The TX-SR604E tested here is the lite' version of the same thing; the bean counters at Onkyo giving it a feature trim to hit a £100-lower price-point.
In reality, this is the actually the base model and the SR674E adds features and tuning to the mix. I certainly liked the GTI version but can this model still tickle the senses?
The SR604E offers a little less power at 90W across seven channels, and gone are the modifications and tweaks specifically tuned for UK ears. Most significantly there is no HDMI upconversion from analogue video inputs on this model, and the setup menus are only output via analogue video connections.
Both HDMI and some sort of analogue video cable will be required between amp and TV even if you have all-HDMI sources.
But don't take those omissions too seriously, because at £400 the SR604 still offers a packed features list. You get excellent connectivity with two HDMI inputs that can break out digital audio, plenty of analogue connections and HD- compatible component video.
The Pure Audio mode that wowed my CD collection on the SR674E is present, too, and you can allocate the surround back channels as active stereo Zone 2 output if desired.
The Audyssey's 2EQ RoomEQ system is retained, along with a mic and fully- automated setup. Painfully, you can't trim or even view the Audyssey values once they have been set with the auto setup routine, meaning if you want to manually adjust the EQ filters you have to start from flat and work it out from scratch using your ears. Frankly, I'd rather be using my ears to listen to a movie.

