http://www.youtube.com/watch?v=2C2FhhZItZ8&mode=user&search=
Found on Youtube. A video of the Optimus Prime Voice Changer Helmet. This user has posted videos of the Cyber-Stompers in action.
From my perspective, the pre-recorded voice on the Helmet and Optimus Cyber-Stomper appears to resemble the voice of the current prime voice, not Cullens. The actual voice-changer sounds horrible, nothing like any of the Primes that I know. The Cyber-Stompers make car noises, and the Bumblebee one plays the original 80s opening theme