With a strings library, every so often you will encounter a note that is slightly out of tune, or not tuned correctly in the context of a certain chord in the music. Has anyone found a real-time pitch correction plugin that works well on strings? I tried the one in Cubase, but I’m having trouble with it adding unwanted artifacts to the sound. Has anyone tried Melodyne or Antares?
Hi,
If you refer to the Sound library (VSTi), then you can use PitchBend to the Monophonic Strings. If you are using polyphony, you can divide it to multiple Channels or you can use Cubase Note Expression > Pitch Bend. The result will be much better, than try to tune it in the audio level.
There are just a few plug-ins which can change the Pitch on the Polyphonic signal. Like Melodyne.
With fretless instruments the chances of finding a handful of people who can play then at perfect pitch is slim - let alone a whole orchestra! 
Hi,
One more idea: you could use the PitchShift MIDI plug-in.