Gil,
On reflection you may be right that Fairchild could have built more than one K-Horn. From the December 27, 1941 New Yorker profile by Geoffrey T. Hellman we have this: "being fond of music, Fairchild has furnished his Long Island house [note, this is the Lloyd Neck house, distinct from the Manhattan town house] with a radio equipped with a loudspeaker intended for a twelve-hundred-seat-theatre..." Also, in reference to the date of completion of the town house,...from the same profile we have this: "Fairchild gave up his triplex apartment a year or so ago and moved to a modernistic house he had built on East Sixty-Fifth Street." This would seem to date the completion of the town house slightly earlier than I thought.
As to the drivers in the unit I saw, I believe I was told they were Western Electric drivers and at least one of the motors (I think it was the woofer) was energized by a field coil instead of a permanent magnet.
Like other forum members I've been interested in Klipschorns and Fairchild for many years. However, I am no expert. I hope that a forum member who knows more of the particulars of this speaker or of Fairchild will be willing to step forward and give us some more information. Unfortunately Dick Long (who had the unit in his possession)has been dead for a number of years.
In 1995 in an attempt to get additional information I contacted Robert Damora who was still alive and had taken the pictures for the Archtectural Forum piece. I wanted to know if there were additional unpublished pictures that he would be willing to sell. Damora, who had become a noted architect in his own right, remembered Fairchild, the town house and the assignment. He did not remember if there were any unpublished photos. At that time he was in his eighties and said he thought he still had the negatives, but if he had them they were in storage, and he had no easy means of finding them. He was very friendly, seemed like a great guy, and I could not bring myself to press him any further for the pictures. I have since seen that the Yale school of Architecture had an exhibition of Damora's work. So perhaps there is a curator out there with additional photos of the Fairchild K-Horn.
Thanks for posting the article.
Peter