Pianos, playable from the console at a variety of pitches and from various manuals and pedals, became a popular addition to theatre organs. The mechanism usually shared much in common with player pianos of the early 20th century, but replaced the tracker bar with a set of exhaust magnets connected to the organ relay.
Some instruments had to make do with an upright piano in the chambers, but the showmanship value of a spotlit grand piano with a mirror placed over keys moved by invisible ‘phantom’ hands proved irresistable to cinema owners trying to get one up on the opposition.
Organ pianos, sometimes from top makers such as Bechstein and Steinway, were both expensive to provide and maintain. Some circuits had only a few pianos which were shipped to whichever cinema had the biggest show on at the time.