It certainly is imaging for me and yes very interesting
Mike with your tests. I wonder then why they are shifting phase like that.
I agree with
Danny too. I use the S1 now and then and I tend to use it in a stereo widening capacity. Last in a chain over a very stereo synth or synth bus. eg a wide pad and the S1 takes it further out etc..I am not a fan of it over a very important buss. eg drums etc..It seems to skew things a bit for me. Detail can get lost and some transients too. It is still good to check mono compatibility over a mono speaker too to see how these things collapse down.
Turning mono sources into nice wide stereo sounds is a different matter and requires some different types of plugs and some effort usually.
Good point
Mike though about using it for panning. There is always another use for something like that.