When transposing audio files without changing the tempo, all editors (including Melodyne) do one of two things:
  • When transposing up, they cut snippets of data out of the audio file
  • When transposing down, they add little snippets of data to the audio file

These additions or subtractions of data is what creates the audible artifacts.

Some do this better than others. Melodyne is a better one, but it still has its limitations. Even with Melodyne it depends on the voice being transposed and the interval of transposition.

It's one of the limitations of audio tracks. Everything has its benefits and price.

Bob


Bob "Notes" Norton smile Norton Music
https://www.nortonmusic.com

100% MIDI Super-Styles recorded by live, pro, studio musicians for a live groove
& Fake Disks for MIDI and/or RealTracks