Panasonic WX-LA20 Manual
Also see for WX-LA20: Brochure & specsManualUsingIntroductionManual
  |
Hearing and Listening in a TypicalClassroom (Summary)Catherine V. PalmerLanguage, Speech, and Hearing Services in Schools July, 1997Vol. 28, pp. 213-217Children spend 45% of the school day engaged in listening activities such astalking, asking questions, and multimedia presentations. The failure we make isassuming that all normal hearing students can hear what is spoken in typicalclassrooms. There are six issues that arise when considering if the students canhear the necessary information in the classroom.1. Teacher’s Delivery: Teachers must speak 15 dB louder than backgroundnoise; however, this is rarely achieved. Many teachers are not able to produce asignal that can be heard over background noise and attempting to do so mayresult in vocal fatigue. This causes teachers to miss multiple days per year.2. Noise in the Classroom: Classroom noise levels should not exceed 35 dBA;however, typical classroom noise levels range from 41 to 51 dBA. In the past fewdecades research has shown little to no improvement in classroom noise levels.The most important characteristic of relevant to effective communication is signalto noise ratio (SNR). Because young listeners (with normal hearing) requirehigher SNRs, it is recommended that classrooms have an SNR of +15 dBA.3. Reverberation: Classroom reverberation times should not exceed 0.4seconds; however, the majority of classrooms have reverberation times between0.4 and 1.25 seconds. Reverberation masks (blurs) direct sound energy. Higherreverberation times cause poorer understanding.4. Distance: Children should be within approximately 6 feet of the teacher inorder to receive maximum intelligibility; however, achieving this distance for allchildren is impossible due to typical class sizes. Speaker to listener distance(SLD) greatly impacts the direct sound field. Children with normal hearing who sitin the middle or back of the classroom have difficulty receiving the speechsignal compared to students in the front row.Continued… |
Related manuals for Panasonic WX-LA20
manualsdatabase
Your AI-powered manual search engine