Graillon 2

KeroVee is a vintage pitch correction tool, established in 2010. It offers a comprehensive feature set, including a MIDI input mode, similar to GSnap. This MIDI input enhances control over vocal pitch, making KeroVee akin to Celemony Melodyne than Antares Auto-Tune. Additionally, KeroVee can function in an automatic "free autotune" mode. However, KeroVee's compatibility is limited to Windows-based digital audio workstations, excluding macOS users. Despite this, KeroVee is an optimal choice for users with older Windows DAWs due to its minimal CPU usage and excellent performance on 32-bit systems.

GSnap is a pioneering freeware autotune plugin that stood as the first free autotune VST in the market. Despite its age, it remains an effective pitch correction tool, similar in design and features to Graillon 2 and MAutoPitch. Its standout feature is the ability to tune the processed audio signal according to the MIDI notes inputted by the user, eliminating reliance on automatic pitch detection. However, it also boasts a robust automatic pitch detection algorithm, even without the formant shifting features present in some competitors. GSnap is exclusively compatible with Windows-based systems and comes with a comprehensive manual for users. It is a reliable option for those seeking a free, user-friendly autotune effect.

MAutoPitch is a robust and flexible autotune plugin. As an alternative to Antares Auto-Tune and Graillon 2, it offers comparable pitch correction features along with additional tools like stereo width adjustment, automatic gain control, and a limiter. This free tool is user-friendly with adjustable speed, range, scale, and depth, and includes a stereo widening feature useful in vocal processing. However, it has a complex installer and its interface is slightly less intuitive than Graillon’s. Despite these minor drawbacks, MAutoPitch's versatility and compatibility with all VST and AU plugin hosts on PC and Mac make it a potential favorite for pitch correction.