weird soundstage with pianos

on both of my systems, it seems as if certain notes on the piano come out of one speaker, then other notes come out of the other speaker. Is this related to how pianos are mic'ed or what?

The soundstage is pretty "accurate" for other instruments, although drums can be a bit oddly dispersed as well.
on certain recordings, pianos are "close-miked" with one microphone on the bass side of the piano and another mike on the treble side of the piano. This sometimes gives the impression of a "40 foot piano" which spans the entire room in the soundstage. The bass notes come out of one speaker, and gradually pan toward the center for the middle notes, and toward the other speaker for the highs.I find this irritating, since I am very sensitive to proper soundstage proportions.
There are VERY few recordings out there which present the piono correctly! Close miking is the most silly attempt. Some recordings try to reproduce the sound as if the pianist would hear it. Some put up two mikes in some distance of the open corpus of the grand. The very best try to carefully adjust both ways so that a "round" and compact sound picture is the result. Try anything by
Dabringhaus & Grimm and you'll hear what I mean.
I agree with the above statements, but I would say that presenting the music is more important than presenting the piano and while it may be annoying for the effect that is being discussed, the close miking can make the music itself more intelligible. Live I want to hear a piano however it sounds. But at home, since I really cannot have that, Im more interested in the music itself. (and still an audiogoner!)
It's definately the recordings and not your set up. I hear the same thing. On some recordings drums span the whole sound stage. So if your speakers are 8 feet apart you'll be listening to an 8-10 foot drum set. With piano's the same, you'll hear a good sound stage for some notes then all of a sudden a note will shoot out of nowhere far away from the rest of the notes. In that case, like Tarsando mentioned it is best just to focus on the music, otherwise you'll just be confused.

Best Regards,
Seems they do this with drums, too. Bass brum, tom-toms from one speaker, high-hat from the other, snare somewhere in the middle. I'm with Tom, this is annoying....
Piano is a bitch to get right. Let go and enjoy the music... peace,warren
Ah, but when it's good, it's good!