A conservation team from the Archaeological Survey of India (ASI) working on a 12th-century Shiva temple in Karnataka's Koppal district has made a startling discovery during the cleaning of the Sabhamantapa (main hall). Two of the four central black basalt pillars were found to be hollow and engineered to produce distinct musical notes when struck, specifically tuned to resonate during the chanting of Vedic hymns.
This 'Sonic Resonance' feature is significantly different from the solid musical pillars found in later Vijayanagara architecture, suggesting that the Late Chalukya architects possessed advanced knowledge of acoustic engineering and stone casting. The restoration project is now using ultrasonic scanning to map the interior cavities of the pillars to understand how the ancient stone-smiths achieved such precise tonal quality without modern tools.