While TC-Helicon can sound somewhat robotic at times, it can also work fairly well if you follow a few basic ideas.

1. Make sure your original vocal recording is in tune. You're not going to get in-tune harmony with an out-of-tune melody. You may have to use GSNAP or some other auto-tuner if you are having problems here.
2. Try to sing it straight; avoid vibrato or scoops or any of the other things you might do. I've found the harmonizer seems to work best when the original is sung pretty straight. Besides, you can always have two versions of the melody (one straight to create the harmonies, the other for the final recording in the manner you normally sing it - of course this version has to be in tune, as well). Base your harmony on the straight version. You can add vibrato to the harmony part when you create it (a whole list of choices there).
3. Keep the TC-Helicon part farther back in the mix. The more you bring it to the forefront, the more robotic it sounds.
4. Use it sparingly.
5. Try to keep the harmony part mostly in the same range as the melody part (within a third or fourth on either side). The further away from the melody it gets, the more chipmunky it gets.

John

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