rbowser
I don't think you've ever said why this quest for Formant shifting is so important to you though - What exactly do you need it for?
If needed for background vocals, and you just want to a bit of the "sped up" or "slowed down" effect and don't need to do precise formant shifts and corrections, there's a highly inelegant but effective workaround.
1. Create a premix of the song that starts at the beginning. Mute all other tracks.
2. Open the premix in the Loop Construction window.
3. From the Clip drop-down menu, enable Stretch On/Off.
4. Move the Threshold slider all the way to the left (0%) so
all the markers disappear. This is very important.
5. The two right-most fields adjust semitones and cents respectively. Do
not enable the Pitch button! That will just confuse things. Cents will adjust +/-49 cents which should be enough. If not, for example if you need to make the pitch 70 cents sharp, set semitones to 1 and cents to -30.
6. Render the clip, and it will reflect the pitch/speed changes you made.
7. After adjusting the pitch, create a track and record your new clip (e.g., background vocals) while monitoring the premix.
8. If you started recording anyplace other than the beginning, slip edit the new clip to the beginning, bounce the clip to itself to add this extra length, then open the newly recorded clip in the Loop Construction window.
9. Repeat step 3, but this time, adjust pitch equal and oppositely. For example if the premix was -36 cents, set cents for the new clip to +36.
10. Bounce the new clip to itself, and now it will be at the correct pitch and tempo but with a different formant and character. You may need to trim the end, as Sonar will still think this is a loop and repeat part of the beginning. You can now delete the premix.