It's a buzzword for a set of speakers to magically sound like another set of speakers.
And it doesn't work worth a hoot (IMHO).
Maybe if they started with a truly excellent sounding speaker and then tried to make it sound like lesser speakers... Still, I'd rather just have truly excellent sounding speakers.
Same with mic modeling. Although I have to admit, I've used mic modeling several times with good results. It won't make an SM-57 sound like a U-87, but if you need a different flavor on a track that's already recorded, it just might do the trick.