Panasonic WX-LT350 The Impact of Sound - Page 3

...cont'd Participants  12 2nd Grade Classes  128 male  114 female  Mean age: 6 years 8 months  43% were from an ethnic background (Vietnamese, Samoan, Spanish, Aboriginal and Torres Strait Islander) Equipment  NAL Twin FM Sound-field Amplification Systems (Type 3032) featuring:  2 Lapel Microphone/Transmitters  Volume controls set to the highest level  4 - 8 Ohm Speakers mounted on the wall Teachers were given an information booklet outlining the project and rationale of using sound-field amplification. Teachers also received in-service training addressing classroom acoustics, speech perception difficulties, 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 midyear and at the end of the year. Classroom Acoustic Measurements Classroom acoustic measurements were carried out in each of the twelve classrooms. The following calculations were made: a) ambient noise levels b) classroom RT measurements, c) S/N ratios in unamplified classrooms d) S/N ratios in amplified classrooms. Occupied classroom noise measurements and S/N ratio calculations were obtained during class time when the teachers and children were in their usual positions during instructional teaching. Continued....