Thanks Patrick, works like a dream now!
You have an "Excitation Only" check box, might be interesting to have a "Noise Only" check box ( produces whispers ).
I've always been fascinated by the Cybermen voices used in the science fiction BBC TV 1967, Patrick Troghton era, Dr. Who story "Tomb of the Cybermen"; they where the most scariest versions of the Cybermen ( in Black & White on a 405 line receiver). I spoke to the guy who created the voices and he told me that they sent a pulse/square wave to a small speaker which was placed in the mouth of the actor who then 'mouthed' the words to produce the effect. I've attached a .wav file from one of the 1967 episodes.
It would be good if you could re-create that effect. I think you've just got to set the Pitch Exciter to a fixed frequency. Have no "noise" and just use the vocal tract K filter. I think the pitch of the .wav file is around 1200 Hz although it would be nice to be able to set the fixed frequency to any value.
Tomb-24k.wav