Tanpura
A four-string drone (Pa · Sa · Sa · Ṣa) to sing and play against. It keeps sounding while you use the other tools.
E4kattai 3329.6 Hz
The four strings sound mandra Pa, madhya Sa twice, and mandra Sa. Pa is the standard tanpura tuning; the first string is dropped to Ma for Ma-based instruments and ragas without Pa. Vocalists usually sit between kattai 1–2.5 (C–C♯/D) for male voices and 4.5–5.5 (F♯–G♯) for female voices; instrumentalists match their instrument's Sa.