South Indian Drone Instrument
The ottu is a south Indian drone instrument. It is very similar to the nadaswaram or the shehnai in construction. It is usually somewhat longer than the nadaswaram. It has a bell, usually of metal like the shehnai. It has four or five holes, which are not fingered but merely occluded with wax to bring the instrument to the correct pitch (shruti). This instrument does not play a melody, but merely provides the drone for temple ensembles composed of nadaswaram and tavil.