Adaptive Time-Scaling:

1. duration change of a voice: original sound, sound slowed down on voiced parts (vowels) and speeded up on unvoiced parts (consonants and noise), sound speeded un on voiced parts and slowed down on unvoiced parts (the duration change is done according to a voiciness criterium),
2. duration change of an instrumental sound (flute): original sound, sound speeded up for high pitches and slowed down for low pitches, sound slowed down for high pitches and speeded up for low pitches.