There is no true way of doing it. It's all about experimenting and having the right tools. For home user, if you're looking at using a solid software, then you should use Audition 3. It comes with a variety of tools and mastering systems. It also has VST-I capabilities but it's not nearly as good as Pro-Tools or Cubase.
Alright, I will try to give you some tips in the right direction.
FIRST RULE: Garbage In = Garbage Oout
1. You need to voice act properly. This means, you need to understand the tone and where the actor has placed the accent. So practice and find the style that you want, it really all starts there. Though I won't lie that in english, solid computerized voice utilize the british way of speaking.
http://www.youtube.com/watch?v=yXWf-l71MY4
(Stevie Ward's voice, beautiful, very sensual but also very neutral)
2. If you're looking to mimic the voice of portal then the first thing you want to do is play with the pitch. Not don't exagerate, just speed it up by maybe 5%, listen and do it again. If you do it right, you can turn a well male voice into a sexy female voice...
3. You'll need to play with the frequency. You can use any frequency filter you want and play around. the more you remove the lows, the closer you'll get to my prior example. Play around and don't be affraid to use the presets already available.
4. Once the pitch and type of voice is there, it's time to add some colors... This is where you need to be gentle and only add a touch of this and that, never got 100% on an effect.
- Graphic EQ
- Phaser effect
- Delay
- Echo
- Flanger
- in Multitrack view of audition, you can use: Vocorder
- Distortion
5. Play around and you'll get it. Make sure to finish with a Multiband Compressor in order to bring or remove the life out of the voice, that's the finishing touch.
You can use any software you want but trust me, when you use the high end, you get high end results. You can have extremely awesome FLstudio songs but place it next to EastWest Quantum Leaps VST-i (some are 80 gigs installation) and you will see some difference in depth, definition and quality. THe big problem is that you'll pay for it... I've just bought Pro-Tools 8 and some VSTs, I'll be eating peanut butter for a month.
Hope that helps.
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