Resonating rocks: The acoustics of Hindu cave temples

Sound has played a fundamental role in Hindu worship since the early Vedic period (ca. 2000 BCE). History indicates that Indian civilizations had a strong oral tradition and relied on knowledge being transmitted through oral means rather than written text. The start of the post-Vedic period (ca. 1st century BCE) was marked by the emergence of temple worship, with rock-cut cave temples among the first structures. While cave temples are critical to the evolution of Hindu religious practices, their acoustics remain an unexplored area. This work addresses the gap by analyzing the acoustics of four Hindu cave temples in the Badami region of present-day Karnataka, Southern India. These caves carved into red sandstone date back to the 6th and 7th centuries CE, with two dedicated to Lord Vishnu and two to Lord Shiva. We analyzed the impulse responses and decay curves measured at Cave temples 1, 2, and 3 in Badami as well as the Ravana Phadi cave temple in Aihole. Standard acoustic parameters like T30, C80, D50 as well as non-standard parameters like resonance quality and resonance width are computed to provide insight into their acoustic properties.