APPLICATIONS & FIELDS OF USE
WALLS & CEILINGS

Architectural surfaces provide another target market for the company. Technical attention to tailored acoustic behavior, namely reflection and absorption, in walls and ceilings is a focus of SmartSkin. Products may be wall and ceiling materials and coverings. The technical team has identified a number of concepts that, when applied to walls and/or ceilings will measurably change the interaction of those surfaces with acoustic energy in the form of sound waves.

The need for acoustically tailored surfaces is strong and growing in our increasingly noisy society. Poor acoustical surroundings raise stress levels, increase frustration and ruin verbal communication. This is a particularly serious situation in classrooms. A recent study by Ohio State University researchers showed that the acoustics of many classrooms are poor enough to make listening and learning difficult for children and that the findings "held across economic boundaries". The classroom problems, which may be equated in many ways to offices and other institutional environments, are reverberation and background noise. When sound bounces off hard surfaces, it creates a masking noise that is additive to the ambient background noise and interferes with speech recognition. Students are sensitive to bad acoustics because they are still learning the language and a small change in the speech to noise ratio can cause a "child to go from understanding almost everything to understanding very little". Beyond auditory effects, classroom noise has also strong physiological, motivational and cognitive effects on children. Additionally, for children with hearing impairment, reverberation of sound off of hard surfaces is an even bigger problem than one of the distraction imparted on a normal-hearing student population. According to Marilyn Neault, Ph.D., Co- Director of the Cochlear Implant Program at Children's Hospital – Boston, "While adult listeners with normal hearing can understand speech in a room with a reverberation time as long as one second, children in general can't have the echo last longer than 0.7 seconds before their ability to recognize words starts to drop. Children with hearing impairment need a reverberation time of no longer than 0.4 seconds to recognize words as well as their hearing allows."

Walls and ceilings in structures such as classrooms have to be both insulating and absorbing. The universal wall covering is gypsum wallboard, e.g. Sheetrock. Gypsum wallboard is an excellent insulator in that sound is not transmitted though the material, i.e. it has a high sound transmission coefficient (STC).

On the other hand it reflects sound well and contributes to the reverberations and other types of background noise that interfere in the learning environment. Sound reflection is measured by the noise reduction coefficient (NRC). Wallboard has a low NRC. The technical team at SSI has identified methods to increase the NRC of wallboard without degrading its STC. It also has designs for ceiling treatments e.g. tiles and other coverings with increased values of NRC.

The Technology is also effective on the other end of the interior acoustic spectrum where reverberation is needed, for instance in a music studio. By embedding sensors and actuators into the surface and applying Energy Flow Control™ technology, the acoustics of a room can be tailored to the satisfaction of the occupant. Reverberation can be enhanced or suppressed at will. This technology forms the basis of the "Acoustically Intelligent Architectural Surface™" concept under development at SSI. The ultimate product in this line will be Acoustically Intelligent Wallpaper™ containing micro-arrays of MEMS (Micro Electro Mechanical System) sensors and actuators powered by microelectronic circuitry embedded in the wallpaper. When properly designed and situated using the Technology, the MEMS will allow noise suppression (STC and/or NRC) at will within a room. The Energy Flow Control™ patent protects this Technology concept.

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