If you're looking for free auto tune software then you've come to the right place.

Andy Hildebrand who developed methods for interpreting seismic data, later realized that his creation could be used to detect, analyze, and modify pitch - little did he know how much his invention would shake up music production (read the full story of Auto-Tune on Wikipedia).

Antares Auto-Tune is the leader, and in my opinion it's still the gold standard, whether it's Auto-Tune EFX or it's big brother Auto-Tune Evo.

Today there are a few similar effects and plugins that you can use for pitch correction, and below is an overview - you can get another list for auto-tune software here and don't forget Auto Tune Evo and Auto Tune for Mac.

KeroVee for Windows Price: Free From: g200kg Pitch-Correction plug-in that works as a VST effect. It can pitch-detect and retune to specified scales or MIDI notes. 'Bypass' and 'SubTone' mix are also available.
AnalogX AutoTune for Windows Price: Free From: AnalogX AutoTune analyses sampled sounds in frequency space to allow you to tune all of your sounds to the same frequency! Just simply enter the note you want to use as the base for all of your sounds, such as C3, and then simply drag your samples onto the application, and WALA! Let AutoTune do the rest! AutoTune can also be used to convert directories, instead of individual files, by simply dragging the directory onto the app
GSnap for Windows Price: Free From: GVST A VST plugin which can be used subtly to correct the pitch of a vocal, or, with more extreme settings, to create a robot-voice effect. For GSnap to work effectively, the input signal should be monophonic, at a good level and reasonably noise-free. For example, a clean, mono vocal recording, without excessive noise or reverb. Effect plug-ins should be placed after GSnap in the signal chain.
MicDroid: Auto-Tune App for Android Price: Free or Donate $2.99 From: Ethan Chen MicDroid is a small Android app that produces the pitch correction effect made famous by T-Pain.

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