Recently, an original long lost manuscript resurfaced having been discovered in an ancient bookshop in the back waters of the southern states.
Ventriloquism – How To Throw Your Voice – Other Voices – Part 5 – Distant Voices
The idea is to make the sound as far back in the pharynx as possible, and to prevent it from rising into the cavity of the mouth by compressing the vocal mechanism. Note well that this voice is low-pitched and is not exploded against the palate as in voice No. 2, or simply muffled as in voice No. 1.
In other words, you always send the sound originating in the larynx in the direction from which you desire it to come—if from above you pitch it high and force it against the roof of the mouth, or hard palate; if from near at hand you make it near by confining it in the cavity of the mouth; and if from below you pitch it low and send it downward. From this it follows that the ordinary drone effect represents distance, while the method used in the projection of that sound suggests direction. In developing these voices, use the vowel and consonant exercise already recommended before taking up the vocabulary.
Some ventriloquists use one distance voice for every effect, and in justification of this plan explain that it is so difficult to execute the distant voice in different keys that, where it is desirable to introduce a number of characters, it is best to do it by transition. That is, they alter the natural tones of the voice so as to make a very apparent distinction between it and the mimetic voice. This can be done so skilfully that the audience will not realize the change, and enthusiastically declare this to be one of the greatest secrets of the art.