I'll still be amazed by what can be done with Max/MSP. I found this program very impressive and gives amazing results, when it's time to make some monster sounds.
Basically, you can record your own voice or import an audio file, and then you're free to play with all modules available, that include granular, spectral shifter, poly pitch shifting, pitch delay, pitch shifting, noise generator, animal convolution, cross synthesis and scrubing cross. All modules work a bit like if there were an effect insert in a mixer, where you can set the volume, pan, solo, mute, and even EQ each single module!
And the goodie is that you can record to an audio file, in real time, while you're tweaking whatever module paramater you want ... so doing a kinda automation in fact. The result can be pretty realistic or totally crazy, depending of the source sound you import (you could import a sound of a spoon hitting a glass several times at different intensity for instance) ... you can be wild with this tool! It's available on Mac and PC ...
... And best of the best ... it's FREE!!!
Here's a demo:
And a technical demo:
For more info and download, please check this website: