Justin Bieber tells a secret. He says record producers use vocal-tuning software “Melodyne” to adjust his singing, but not AUTO-TUNE, reports contactmusic.com
Justin is said that he refuses to use Auto-Tune, the popular audio processor utilized by other singers including Britney Spears, but recording studio engineers correct the pitch of his singing with Melodyne software.
Justin said:

“I don’t use Auto-Tune.
“They tune my vocals – they use Melodyne. But every artist uses Melodyne. Not every artist, but 99 per cent of artists. I like the sound, the perfectness of tuning in the record. No one has completely perfect pitch.”