Robot Voice Text To Speech

Hi, 

Can anyone point me in the direction of a good (free or very cheap) text to voice or voice changing software or app (android, ios or Mac) or even Windows. 

I need to make lots of recordings for a robotics project so I need a deep husky sound like the ABC Robot from Judge Dredd, or even the Guard Towers from Aspen Prison of the same film. 

The recordings will be played back to an ios Morfo app of a robot head to help give an animated face to my robot. 

 

Thanks 

On Linux there is eSpeak. It
On Linux there is eSpeak. It might be portable to MacOS.

Festival might also work.

Thanks all, I have been

Thanks all, I have been looking at some YouTube guides for Audacity using vocoder and playing with Mac Voiceover. 

Some good results just need to sort out which to use and make some recordings.

I can then play the sound clip and make a Morfo video recording (lots to be precise) .

 

Then all I need to do us work out how to play video clips seamlessly from within a Python program.