On Fri, 2013-01-11 at 16:20 -0200, fls(a)rendera.com.br
wrote:
  Hi Julien and folks
 There is an old trick to help to "tune" vocals. You replicate your vocal
 track twice. In one of the copies you add a LADSPA Rubberband pitchshift
 with +5% and to the other you add the same plugin with -5%. Mix these
 untunned channels with a low volume, like 20% of the original one.
 How this workaround help? Once that you try to reach a note, you have 3
 chances to it. Our earing will listen only the right one. Normally 5% of
 pitchshifting is enought to correct small mistakes. Take care to not put
 the replicas too loud. 
 Ouch! The above will cause some kind of chorus effect that isn't wanted
 for every song, perhaps
 
http://kokkinizita.linuxaudio.org/linuxaudio/zita-at1-doc/quickguide.html
 does work, I don't use auto-tuners myself, so I don't know. However,
 this might be a case when auto-tune is useful, I didn't listen to the
 recording.
 Hth,
 Ralf
 
Hi Ralf
Yes, it causes a chorus effect and a kind of soft vocal effect. I agree,
it isn't wanted for every song. I use to call it Paul McCartney vocal...
:-)
Best
schiavoni