Importance of Acoustics

Posted by Syl_ai on May - 21 - 2011

Acoustical Quality And Student Learning

Good acoustical quality in classrooms is critical for student learning. Research has shown that noise exposure affects educational outcomes and provides evidence of mechanisms that explain the effects of noise on learning. Speech intelligibility studies indicate that students’ ability to recognize speech sounds is decreased by even modest levels of ambient noise, and this effect is magnified for younger children. This problem is frequently not appreciated by adults, who are better able to recognize speech in the presence of noise. Most learning activities in school classrooms, especially for younger children, involve speaking and listening as the primary communication modes: Students learn by listening to the teacher and to each other.

Excessive background noise or reverberation (i.e., multiple delayed reflections of the original sound) can interfere with speech perception and thereby impair learning. Careful attention to acoustical design requirements, then, is essential for creating an effective learning environment. Nonetheless, a 1995 report of the U.S. General Accounting Office estimated that the acoustical quality in approximately 22,000 U.S. schools attended by 11 million students was unsatisfactory. Figure 6.1 illustrates the four typical major sources of noise in classrooms and reflected speech sounds (reverberation). HVAC systems are perhaps the most common source of ambient noise in classrooms. However, significant levels of noise can also be transmitted through walls and windows from outdoors or from adjacent indoor spaces. Reflected sound within a classroom, if uncontrolled, degrades speech intelligibility.

One way to describe the desired acoustical quality in a classroom is to specify an acceptable maximum ambient noise level. This level is measured in terms of A weighted sound levels or octave band sound levels that can be used to determine other measures such as noise criterion (NC), room criterion (RC), or balanced noise criterion (BNC) values. By combining the effects of sound at different frequencies in a manner similar to that which takes place in the human hearing system, these measures rate the loudness of sound to listeners. A second way to describe acceptable room acoustical quality is to specify the reverberation time, which is approximately the time it takes for a loud sound to die awa after the source is turned off. Reverberation times increase with room volume and decrease as sound-absorbing material is added to a room. However, excessive sound-absorbing treatments will have the negative effect of reducing speech levels and degrading the intelligibility of speech in a classroom. People’s ability to understand speech is influenced largely by how loud speech sounds are relative to ambient noise or any other competing sounds, hence the importance of an adequate signal-to-noise ratio (i.e., speech to background noise ratio) for a classroom to function well. Reverberant sound causes one word to smear into the next and can decrease the intelligibility of speech.

Acoustical design should be aimed at improving the recognition of speech sounds in the classroom. The focus should be first on reducing unwanted noise. Good acoustical design can facilitate learning by allowing for more accurate verbal interaction and less repetition among teachers and students because spoken words are clearly understood. There is also evidence that good acoustical design may have a health benefit for teachers by reducing the potential for vocal impairment, and it may have the ancillary benefit of reducing teacher absenteeism. Learning things is not limited to the scientific area. Instead it also has relations with some other things like speaking a language or using software, including Rosetta Stone Japanese and Rosetta Stone Korean. If you have a creative mind, you will make all your own differences in the end!

Article Source: http://www.articlesbase.com/k-12-education-articles/acoustical-quality-and-student-learning-4681525.html

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