Musiclover, I have Melodyne Plugin and occasionally make harmonies this way. You're right, you can't just universally move the blobs. I'm a guitarist and I sit and work out appropriate harmonies and then move the blobs accordingly; it all depends on the key you're in of course. Having said that I find that artifacts kick in if I move notes more than a couple of tones with warbling/chipmunk shades creeping in. Although this can be masked within the mix, I find the method that works best for me is to work out harmonies, record them and then use Melodyne to make corrections; this way I don't have to push and pull the blobs too far so the result doesn't have any chipmunk giveaways.

John

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