We start of by duplicating the verse or part of the vocals you want to give the effect too. On the part you have duplicated we have to change a few setting to do this.
At the bottom left corner in Ableton we have to change the following. If WARP isnt yellow, turn it on. Change the WARP MODE to PRO, Formats and Envelope to a low value and then the Transpose macro to -12.
You should have something similar to the audio example below.
We now need to layer this with the original version, we also have grouped these two together and added a reverb and vocal compression from the GO TO COMPRESSION PACK which sounds like this :-
You could use this in a multitude of ways, try using this with the main parts of the vocals by cutting and the parts on the lower octave vocal as in the example below shows.
fake vocal double.
Using a vocal double in a track give the vocal mix a more pleasant sound and adds richness to the mix, if how ever you have done the main vocal but haven't got time to do another take on doing the double's then here is a quick tip for getting it done fake style.
Firstly we need to copy the vocal onto a new track (above fig 1), place a auto tune device and delay the input by around 15 to 50 ms (below fig 2).
You can then adjust the panning and alter the volume of the double track to suit your production.