text: Harmonium The immediate predecessor of the electronic organ was the harmonium, or reed organ, an instrument that was common in homes and small churches in the late 19th and early 20th centuries. In a fashion not totally unlike that of pipe organs, reed organs generate sound by forcing air over a set of reeds by means of a bellows, usually operated by constantly pumping a set of pedals. The Harmonium used pressure, and the American reed organ or pump organ used suction.  While reed organs have limited tonal quality, they are small, inexpensive, self-powered, transportable and self-contained.  (Large models were made with multiple manuals, or even pedal boards; in the latter case, the bellows were operated by a leaver or crank on the side by an assistant, or in some late models an electric pump.) The reed organ is thus able to bring an organ sound to venues that are incapable of housing or affording pipe organs. This concept played an important role in the development of the electric organ.
  Pipe organ
  In the 1930s, several manufacturers developed electronic organs designed to imitate the function and sound of pipe organs. At the time, some manufacturers thought that emulation of the pipe organ was the most promising route to take in the development of an electronic organ.  Not all agreed, however.  Various types of electronic organs have been brought to market over the years, with some establishing solid reputations in their own niche markets.
  (1897–1930s)
  The use of electricity in organs emerged in the first decades of the 20th century, but it was slow to have a major impact. Electrically powered reed organs appeared during the first decades of electricity, but their tonal qualities remained much the same as the older, foot-pumped models.