Consider the following statements regarding sound wave propagation and audible enclaves:

1. When sound waves travel through a medium, they spread out due to diffraction, influencing their direction and intensity.

2. Audible enclaves are localized pockets of sound that can be heard only by specific individuals without affecting the surrounding noise environment.

3. Lower frequency sound waves, rather than higher frequency ones, tend to spread out more rapidly as they propagate, making them more difficult to confine within a directed beam.

Which of the statements given above is/are correct?

The correct answer is option 4.

In News

• A study published in the Proceedings of the National Academy of Sciences introduced the concept of "Audible Enclaves," a new sound technology that enables localized sound delivery without external disturbance.

Key Points

• Diffraction causes sound waves to spread out as they travel through a medium, affecting their propagation and intensity.
  • Hence, Statement 1 is correct.
• Audible enclaves refer to small, focused sound zones that are not disturbed by surrounding noise.
  • They work by using two high-frequency waves of different frequencies that are inaudible individually but produce an audible wave at their intersection point due to non-linear interactions.
    • Hence, Statement 2 is correct.
• Higher frequency sounds diverge less, making them easier to direct into narrow beams.
  • Lower frequency sounds actually spread out more, which is why low-pitched sounds (e.g., bass) can be heard from a greater distance, even through walls.
    • Hence, Statement 3 is correct.

Additional Information

• Parametric array loudspeakers use self-demodulation principles to focus sound into beams, allowing for private listening experiences in public spaces.
• Potential Applications of Audible Enclaves:
  • Museums, shopping malls, and transport hubs for delivering targeted audio content.
  • Military and security communications for covert sound transmission.
  • Virtual reality and augmented reality systems for immersive, location-specific audio experiences.