The walls have ears : Golconda Fort and its eerie acoustics

The Golconda fort situated in Hyderabad is a 500 year old fortified citadel renowned for its incredible acoustics. The fort was home to the Qutb Shahi dynasty for over 200 years. It was built by the king Ibrahim Quli Qutb Shah who was an expert in physics. With the help of Iranian architects well versed in acoustic technology he built this marvelous sound alarm system.

In Golconda even today, the sound of a clap or a faint whisper travels from the entrance till the 400 feet high citadel. That's how far ahead of its time the architectural and sonic integrity of this fort was and still is. People unaware of it’s mysticism can easily be spooked by sounds that don't seem to have a face.

Golconda was built very carefully and cleverly by applying meticulous science to its architecture. It was constructed by mixing shards of earthen pots, pans and also metals to stone as the had brilliant sound reflection properties.

The entrance portico of the fort also has a series of arches, each smaller than the previous which ensures the sound entering the dome is first compressed and then amplified to a long distance. It also has a diamond shaped geometry which is specially designed to cause maximum sound vibration.

By using arched doorways as parabolic reflectors this unbreakable security system of the fort was reinforced. This ensured smooth communication between guards during the time of an attack and also helped the army commander know what the sentry was doing.

Golconda was considered impregnable during its prime day as even the Mughal emperor Aurangzeb was not able to conquer it during his first two attempts. He finally conquered it the third time with the help of a traitor security guard which ended in the historic siege of Golconda.

This fortress was also situated on the famous trade route where trading of diamonds excavated from the nearby Kollur mine took place. 13 world famous diamonds including the Kohinoor were stashed here. This was another reason why there was a need for this ultra security.

It's hard to believe that half a millennium ago when no electronic devices existed, this revolutionary acoustic system could alert a surrounding of upto 3 sq.km radius without wireless technology.