How do I make sounds slower/deeper?

In the Audio plugin there's an action named "Set Playback Rate". A value of 0.5 makes the sound playback at half speed (lower pitch & slower tempo), a value of 2 makes it play at double speed (higher pitch & faster tempo).

I don't believe there's a way to change the tempo or pitch separately by default in C3.

Thank you very much. I'll try it. :)

Hi, you can try this video tutorial