Here's a piece I found googling for "meantone temperament" http://www.youtube.com/watch?v=e2XNAJPgqhU http://www.youtube.com/watch?v=e2XNAJPgqhU You might be

Here's a piece I found googling for "meantone temperament" http://www.youtube.com/watch?v=e2XNAJPgqhU http://www.youtube.com/watch?v=e2XNAJPgqhU You might be able to pick up the difference in tuning. As for being able to hear when something is "out of tune," everyone has a different ability to pick up on subtleties like that. In some cases, I'd guess you hear a pitch when it's wrong, it just doesn't bother you enough to make a judgment on it so you don't remember hearing it.