Michigan State Gazette, January, 1906, page 3:

THEATROPHONE
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   During the past month two or three special circuits have been provided between the theatres, the churches, the Light Guard Armory, the new Penobscot Inn and the residences of several officials of the company, for experimental purposes. and the results, considering the class of equipment have been fairly successful. Some little difficulty has been caused by the extreme sensitiveness of the transmitters used and the difficulty of locating them in the most favorable places; but these obstacles will undoubtedly be overcome, and it is believed that eventually a new use for the telephone will be will be developed along these lines. It has been discovered that the acoustic conditions existing in the churches are superior to those in the theatres, and for that reason the transmission of the church services has been particularly successful. In the theatres the reflection of the voice from the walls and set scenes has somewhat marred the clear transmission tones necessary to a thorough understanding of what is going on. Further experiments will be made and their results announced from time to time in the Gazette.