Carrington, Hereward (1907). The Physical Phenomena of Spiritualism. Herbert B. Turner & Company. p. 201. "In the vast majority of cases, the trumpet talking is done by the medium himself. If the séance is in the dark, the medium’s task is an easy one, he having only to wave the trumpet about and imitate whatever voices he desires. By attaching a trumpet to the end of the telescopic rod... and moving this about, voices can be made to appear in various parts of the room at will. Sometimes the trumpet is partly in sight, when the room is only partially darkened, and yet the voices come. This is accomplished by a small piece of rubber tubing being attached to the mouth of the horn, and the medium speaks into the other end of this tube. The voice appears to issue from the horn. At other times the medium employs a second trumpet, speaking into that, and it is almost impossible to distinguish the difference by locating the sound. At other times the medium consents to be held by two sitters while the horn is doing the talking. When this is the case, the medium generally has a confederate, who manipulates the horn, does the talking, etc."
