I'm not sure what Sharkman is talking about but everything you need is built into this deck. It is very confusing at first but the more you play with the Hu you will notice that setting the various features requires the same keys or buttons. It doesn't come with one push of a button anymore at least not with this unit, but with a series of sequential pushes and a rotation or two or three...of the knob. Setting the time correction is a bit tedious and does require some measurement from your head height to the individual speakers. A refence chart is given to help with the settings. You can do this from multiple positons in your car ie Drivers seat, passenger seat or rear with multiple settings. In short, it time delays the speakers closest to your ears and matches it with those furthest away so it sounds like your sitting in a room directly in front centre of your speakers. It opens out your soundstage.

All in all I am blown away with it's potential on my stock system. The biggest change is the detail and clarity. I actually notice time and space in my music. The hang time in cymbals, the time and pauses between notes.
All my cd's sound different to me.
Again for the money BANG FOR THE BUCK!!!
Sheldon