- Harmoniums are keyboard operated reed instruments which are powered by wind bellows
- The bellows can be foot operated or, with the Indian instruments, by hand
- The Victorian British introduced the harmonium to India as a more stable alternative to the piano in a humid climate
- The instrument was then developed in a more portable form with the addition of drones to accompany singing
- The shruti box is just the drones without the keyboard and is great for setting a background to sing or play a melodic instrument against