Take Pioneer's VSX-AX4ASi, strip off a few inputs, lose the second zone remote and shave £150 off the price - and what have you got? Yup, the new VSX-AX2AS.

Blink, and you miss the differences between the two inside and out. Features like HDMI switching, video upscaling, an iPod dock cable and Advanced MCACC RoomEQ are common across the two. They have both been breathed upon by AIR studios, with standing wave, reverb and phase control, and both wear a THX Select2 badge.

So what's different? Around the back there is one less HDMI input, now down to three, and one less audio input. And the removal of both iLink and USB ports might be a pain if you have a top-spec Pioneer DVD player or a perverse desire for playing compressed music files from a USB drive.

Pioneer also claims 10W per channel less power on the VSX-AX2AS. That puts it down to 170W - our Tech Labs reveal it is 175W - identical to the AX4...

That model had 'issues' when I reviewed it a few months ago, so I accepted the near-identical AX2AS with some trepidation. I liked the AX4 for its power and features, but the MCACC RoomEQ had the electronic equivalent of a bad hair day, applying bizarre filtering that left the sound with dry bass and ear-syringing treble. Would I be in for more of the same?

Simple setup

Setup is delightfully straightforward, and if you want to go for the full auto-everything mode it takes hardly any time at all. The auto setup applies all the usual speaker checks, including relative volume levels, distances and size, runs the MCACC across all channels, applies the reverb and standing wave control and saves the data to one of six memories.

From here you can delve into the manual modes to tweak every setting - which, given the sheer number of filters, channels and adjustments could take you an ice age.

Sadly, the menus and graphic plot displays are all dull monochrome, but if you get the urge you can export the data to a PC using Pioneer's free download software and an RS232 cable. This gives colourful 3D plots of the output of each channel and suggests why some anomalies occur while offering ideas on how to avoid them.