I,ve had the casio 6200 for about a year now , and I am still discovering new things about it,when layering tones,the sound you get depends on which tone is layered on top, perhaps what i am stating is obvious to lots of you on here, if so I apologise, but to me if, for example, I layer a piano tone on top of a trumpet sound, it sounds distinctly different from layering a trumpet sound on top of a piano sound, the top tone appears to dominate, yet more permutations to play around with.