SL Tune is a vocal pitch-correction and tone effect for iPhone and iPad. Insert it on a vocal track in a compatible AUv3 host. Choose a key and scale, or select the allowed notes yourself. Natural mode preserves small pitch movements, Hard gives faster correction, and Robot locks pitch to the selected root across octaves. Six controls shape the sound: Retune, Humanize, Formant, Snap, Echo and Mix. Formant changes the tonal balance. Mix blends processed and original audio. Start with one of six factory presets: Classic Hard, Trap Lock, Silk Vocal, Clean Fix, Robot Grid and Echo Adlib. Save and load your own presets locally. The resizable interface adapts to portrait, landscape and compact host windows. Use SL Tune as an AUv3 effect in a compatible music host, or open the standalone app to preview and adjust the controls. Pitch correction works best on a single vocal line. It is not designed to tune a complete mix or separate voices from background music.