Guitarpima
Wouldn't it be easier to clone the mono track, offset one clip a bit and get the same effect?
No, because it not the same sort of thing. Firstly when you start cloning and delaying one side it is when you get into mono summing all sorts of things happen. Comb filtering effects, the tone of the sound can change dramatically. Strange things can happen in mono. You may say what if we are in stereo all the time and we don't sum. Things seem to sound a little better if they can be wide but at the same time they collapse into mono well. The clone/delay thing does not always satisfy both of those requirements well. Other methods of creating stereo imaging can.
I think it may be more frequency dependant, dividing parts of the spectrum up and panning those sections, keeping things below a certain lowish frequency in mono and centered. I guess they might be adding some very tiny delays here and there in various frequency bands etc..They say they are trying to replicate the sound as if two microphones recorded it rather than one. There does not seem to be any timing differences in what they seem to be doing. So it all ends up wide and interesting and still sounding great and robust in mono.
What is cool is that there is a whole bunch of factory presets just related to turning mono into a wider image and they all sound quite different!
I also love a free program called SHEPPi by Bob Katz.
http://www.kvraudio.com/product/sheppi_spatial_enhancer_by_open_ambience_project It does a fantastic job too of giving mono sources real width. They do it by working with early reflections a lot and it is a fine approach as well. You can tweak SHEPPI quite a bit for different results.
I am keen to hear both in series for example. (or parallel PSP followed by SHEPPi. (or other way around) It means less work for each of them too for a stronger result.