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The Impact of Sound-Field Amplification 
(Summa

ry) 

 
Dillon, Harvey and Robyn Massie 
Australian J of Education, 50(1):62-77     2006 
 
Introduction 

The goal of classroom instruction is comprehension. In order for speech to be 
comprehended, the individual must be able to hear well enough to discriminate 
the word-sound distinctions of individual phonemes. Poor comprehension in the 
classroom is not, however, limited to those with hearing loss. Young listeners 
perform more poorly in noisy situations than do adults and the ability to listen in 
noise is not fully developed until adolescence. A child’s auditory brain is not like 
an adult’s until about the age of 15; therefore, children cannot rely on years of 
language and learning experiences to fill in the gaps of missed information. 
National Acoustic Standards in the United States require classrooms to meet the 
following acoustical standards: 
 

Noise Level: 

35 dBA 

 
Reverberation Time: 

< 0.6 seconds (medium-size rooms) < 0.7 seconds (large-

size rooms) 

Signal to Noise Ratio: 

+15 dB.  Studies have shown that actual classroom 

conditions range from 41 to 69 dBA which lead to unfavorable Signal to Noise 
ratios and reverberation times. 

 
Communication in Cross-Cultural Classrooms 

Individuals for whom English is a second language (ESL) experience greater 
speech perception difficulties. ESL students performance has shown to be poorer 
across most classroom listening conditions. Understanding spoken English in 
noise is related to the individual’s proficiency with the English language. 

 
Sound-field Amplification 

Sound-field amplification is an exciting educational tool that allows control of the 
acoustic environment in a classroom allowing acoustic accessibility to teacher 
instruction for all children in the room.  Originally designed as an assistive  
 
 

 

 

 

 

 

 

 

 

Continued… 

 
 

Summary of Contents for WX-LA20

Page 1: ...andards in the United States require classrooms to meet the following acoustical standards Noise Level 35 dBA Reverberation Time 0 6 seconds medium size rooms 0 7 seconds large size rooms Signal to Noise Ratio 15 dB Studies have shown that actual classroom conditions range from 41 to 69 dBA which lead to unfavorable Signal to Noise ratios and reverberation times Communication in Cross Cultural Cla...

Page 2: ...classrooms it was found that non native English children with normal hearing sensitivity was significantly improved at speaker listener distances of 12 and 24 feet and significant improvements were shown in speech intelligibility The benefit of the dual channel transmission system is that two teachers can use the system at the same time or the second microphone can be handed around among the child...

Page 3: ...ulties suggestions for management and practical demonstration of the sound field amplification systems Audiological Assessment Hearing screenings were performed on all the subjects at the beginning of the school year The same screenings were performed on 25 of the children mid year and at the end of the year Classroom Acoustic Measurements Classroom acoustic measurements were carried out in each o...

Page 4: ...of teachers used amplification for more than one hour but less than two hours each time Twenty five percent of teachers reported using the systems for more than two hours each time Results To reduce inflated results from outlying sources the mean skill increases were calculated to get a true indication of how many skills were gained through amplification Once the means were established it the fina...

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