Now i want to change a pitch(tonality) of a song?
What kind of song? Is it an audio file or a GarageBand project?
GarageBand 10 does no longer support transposing audio files.
You can convert your audio file to a loop or use the AuPitch filter.
- To add the audio file to the Loop Library trim it to an exact number of measures. Then select it and use the command "Edit > Add to loop library".
- Make sure the type "Loop" is selected and not one-shot.
- Click "Create". Now you can delete the original region and add the loop from the Loop Browser. And now the Transpose slider should work.
To transpose using the AuPitch filter:
- In the new GarageBand you add the AuPitch filter from the Smart Controls.
- Enlarge the SmartControl panel by dragging the dividing line upwards, until you see the Audio Units brick, then add an Apple Audio Unit and set it to AuPitch.