Harmonium
Harmonium is an Indian Reed instrument and is a common member of the Indian orchestra. Harmonium is of the Reed organ family in which the air from the hand-operated bellows causes the metal reeds to vibrate. Harmoniums can be used to play chords, melodies, and drones, either separately or all at once.
Harmonium consists of a wooden cabinet, usually made of teak, which houses the reeds mounted on a frame. The air chamber consists of several moving components which are made of wood. The quality of wood and the workmanship is very important, as poor workmanship might result in jamming of keys, leakage of air and also bad sound. Till the 1940s, only German reeds were used in harmonium, as good quality reeds were not manufactured in India. Only from the 1940s, good quality Indian reeds were manufactured in Palitana, a town in Gujarat.
Depending on the number of reed sets, harmoniums can be broadly classified into three types: single Reed, double reed, and triple reed.
Single Reed Harmonium
The single reed harmonium is the basic type which has got only one reed set and is commonly used by beginners and some bhajan singers too. The single reed harmonium only has a male range (C2-C5).
Double Reed Harmonium
The double reed harmonium consists of two sets of reeds and is the most commonly used type by the singers. The dual reed set offers two sounds, with a sound interval of an octave- lower or higher depending on the build of the instrument. Some double-reed harmoniums will also have the feature of drone built into it, i.e. the harmonium can produce drone without playing any keys, like a shruthi box.
Triple Reed Harmonium
The triple reed variant, as its name suggests has three sets of reeds and has got a complex construction and mechanism. The triple reed often comes with a scale changer (an option to transpose like in the electronic keyboards). The scale changer has two variants- 9 semitones and 13 semitones.