Harmonium (extra superior) made entirely by hand.

A harmonium or trap organ is a keyboard instrument that belongs to both the lamellophones and the aerophones. Like the accordion, the harmonium is a development from the Orgue expressive, which was invented by Gabriel-Joseph Grenié. The name harmonium was introduced by the Frenchman Alexandre Debain, who in 1840 for the first time made such a keyboard instrument based on pressure wind with resounding reeds. Debain even tried to protect the name harmonium by means of a patent. In the United States, about the same period, a similar instrument was developed, but with suction wind, which is known there under the name reed organ, parlor organ, pump organ, cabinet organ or cottage organ. The suction wind technique produces a softer sound that is more suitable for living room use. In addition, a suction wind harmonium was cheaper to build, so that this type gradually supplanted the pressure wind model. Instruments with pressure wind technology were used in concert halls, salons and churches. The harmonium was also widely used for singing accompaniment, especially as a surrogate organ for domestic worship. However, it lost its popular position to electronic organs and other instruments. Since the end of the twentieth century, there has been renewed interest. Well-known players are Joris Verdin, Bart Rodyns, Dirk Luijmes and Johannes-Matthias Michel. The Harmonium Museum Netherlands is located in Barger-Compascuum. Just like a harmonica and an accordion, a harmonium is an aerophone and a lamellophone at the same time. The sound is created by the resonance of the reeds and the air vibrations caused by the moving tongues. An organ, also called a pipe organ for distinction, is an aerophone in which the sound is created only by the resonance of the air in the pipes. Organs can be very large and are permanently installed in a church or concert hall, a harmonium is about the size of a piano.