Download - Basic Classroom Acoustics
![Page 1: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/1.jpg)
Basic Considerations in Classroom Acoustics
![Page 2: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/2.jpg)
Acoustic Factors to Consider
● Distance between talker and listener● Level of signal● Signal-to-noise ratio● Reverberation● Physical Barriers
![Page 3: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/3.jpg)
Effective Signal and Effective Noise● 4 primary considerations for relating speech perception to
room acoustics
– Effective signal is both incident speech signal and its early reflections
– Effective noise is both background noise and late reflections of speech signal
– Dynamic range of speech ~30 dB in any given frequency band
– Proportion of speech signal exceeding effective noise allows for estimate of speech perception independent of patient characteristics
![Page 4: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/4.jpg)
Effective Signal and Effective Noise● 4 primary considerations for relating speech perception to
room acoustics
– Effective signal is both incident speech signal and its early reflections
– Effective noise is both background noise and late reflections of speech signal
– Dynamic range of speech ~30 dB in any given frequency band
– Proportion of speech signal exceeding effective noise allows for estimate of speech perception independent of patient characteristics
![Page 5: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/5.jpg)
Reverberation
● Reflections – early and late
● Early reflections ~80 ms or less
● Late reflections more than 80 ms
![Page 6: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/6.jpg)
Reverberation and Distance● Early reflections contribute to effective signal
● Early reflections important for speech perception because they are constant in level throughout room.
● Direct signal follows inverse distance law – sound pressure is inversely proportional to the distance from the sound source
p 1/r∝
● Sound pressure decreases by 6.02 dB for every doubling of distance from the sound source
![Page 7: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/7.jpg)
![Page 8: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/8.jpg)
![Page 9: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/9.jpg)
![Page 10: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/10.jpg)
![Page 11: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/11.jpg)
![Page 12: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/12.jpg)
Classroom Acoustics-Effective Noise-
![Page 13: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/13.jpg)
Classroom Acoustics-Effective Noise-
Reverberation time of room determines equivalent noise level for late reflections
![Page 14: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/14.jpg)
Classroom Acoustics-Effective Noise-
Reverberation time of room determines equivalent noise level for late reflections
![Page 15: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/15.jpg)
Classroom Acoustics-Effective Noise-
![Page 16: Basic Classroom Acoustics](https://reader031.vdocuments.net/reader031/viewer/2022020110/54bcf51e4a7959af4c8b45d3/html5/thumbnails/16.jpg)
Classroom Acoustics-Effective Noise-