That is not just a simple sound effect, but quite a lot of manipulation. It sounds like they have made heavy use of resonant filters, possibly an auto-tune effect, and reverb.
Here a little sample (attached) of a similar (but different) effect using Audacity 1.3.5
The method used here was:
1) Recording of baby
2) Normalize
3) Select very short part between
zero crossing points and repeating them between 20 and 100 times - this draws out some "notes"
4) Apply the Leveller effect (set to "heavy") a couple of times to even out the volume.
5) Amplify by -30dB (the next effect will create a lot of gain).
6) Apply several "comb filters" by entering similar code to this in the "Nyquist Prompt"
Code: Select all
(scale 0.5 (sim (comb s 0.5 275)(comb s 0.5 220)(comb s 0.5 330)(comb s 0.5 375)))
If the resulting sound is too loud and clips, reduce the "0.5" to a smaller value where it says "scale 0.5"
Changing the numbers (275, 220, 330, 375), will result in different sounds.
7) Apply the Leveller effect again.
For more information about Nyquist programming, see here:
http://audacityteam.org/wiki/index.php? ... t_Plug-ins