Calcutta Style Scale Changer Harmonium
Reed Banks
Most harmoniums used for kirtan have two banks of reeds, called 'bass' and 'male'. The bass reeds are the lowest octave with the low C on the keyboard usually being C2 (65.41Hz) with the male reeds being one octave higher than the bass or low C having a frequency of C3 (130.81Hz). Calcutta style harmoniums often have three banks of reeds, which can be two male reeds banks and a female bank. Others will have bass, male and a female bank. The female bank would start on C3 (261.63Hz). This can vary between manufacturers.
Scale Changer Keyboard Mechanism
The picture to the right shows the more complex keyboard mechanism found in a scale changer harmonium. The picture below it shows the scale changing (shifting, not really changing the scale) lever.
The keyboard can be lifted and moved left or right up to four “keys” by means of a lever in the middle and below the key board above the stops knobs. This allows the musician to play the keyboard in the key of “C” but transpose the pitch up or down by semi-tones.
Each key has a lever which rises up when the key is pressed. The lever is part of the coupler mechanism.
Each key pivots on a small horizontal pin so that the key lever at the far end of the key lifts up when a key is pressed. The far end sits under what I call the 'lifters' which sit above oval holes. The reeds for that note are mounted on the bottom of the keyboard tray so when a key is pressed, the lifter releases air from the bellows to and the reeds vibrate creating the desired note.
In this picture, the keyboard levers are above the lifters, which is not the normal position. I needed to remove two keys to replace the plastic tops so positioned the keyboard levers above the lifter arms.
Scale Changing Lever
Calcutta Key Springs
The key springs which help block the air flow when the key is not pressed are not on the top of the key like in Delhi style harmoniums, but buried underneath the lifters in the back. See the next section for more information.
