QuietRock sound dampening drywall.
But now out of China comes word of a product that can dampen specific frequencies of sound.
In the January 26, 2010 issue of Applied Physics Letters, Z. Yang, H. M. Dai, N. H. Chan, G. C. Ma, and Ping Sheng of the Department of Physics, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong announced to the world that they have developed lightweight multi-pane plastic frames covered in latex with a small weighted button mounted in each which vibrate in response to sounds within a specified frequency. They report that a stack of their panels 2 and 1/3 inches thick, weighing less than 4 pounds per square foot will reduce sound transmission by 40 decibels over a range from 50 hz (close to the frequency of a G note 2 octaves below middle C) to 200 hz (close to the frequency of the G sharp note immediately below middle C).
A 40 decibel drop in volume is like reducing the sound of a motorcycle down to the volume of normal conversation or dropping the sound of hair dryer down to the volume of a whisper.
Imagine how these panels could be used. They could provide a reasonable level of privacy in small homes and make a big difference in multifamily living. They are definitely being added to my wish list. Even in a naturally built house with thick walls they could make a big difference internally, for instance to isolate the sound originating in a child's room or to absorb the sound from noisy appliances such as refrigerators.
Read more about the panels in the article Latex could silence noisy neighbors in New Scientist and in a Popular Science article, Acoustic Meta materials Could Make Ultra-Thin, Ultra-Effective Noise-Cancelling Panels.
Photo by BarelyFitz used under creative commons license.