Many researchers have stressed that the acoustic environment is crucial to the speech perception, academic performance, attention, and participation of students in classrooms. Classrooms in highly urbanised locations are especially vulnerable to noise, a major influence on the acoustic environment. This study investigates the noise levels in one such urban environment, Hong Kong. The ambient noise level, and its relationship to the speech intensity levels of both teachers and students was surveyed in 47 primary school classrooms. Moreover, the presence of acoustical treatments for noise reduction and the use of classroom amplification systems were documented for each classroom. The survey found that the mean occupied noise level was 60.74 dB (A); the mean unamplified and amplified speech-to-noise ratios of teachers were 13.53 dB and 18.45 dB, respectively; while the mean unamplified speech-to-noise ratio for students was 4.13 dB. Most of the classrooms exhibited insufficient acoustical treatments to provide significant noise reduction. The listening environment in many Hong Kong primary schools was not favourable for optimal classroom learning. Recommendations for improving the acoustical environment in classrooms in highly urbanised locations such as Hong Kong are discussed.
[Copyright of International Journal of Disability, Development and Education is the property of Routledge. Full article may be available at the publisher's website:
http://dx.doi.org/10.1080/10349120500348714]

Background noise poses adverse effects on speech sounds and affects student learning, especially for children with developmental disabilities. Sound-field and public address amplification systems can help to solve this problem by amplifying speech sounds relative to background noise. This study surveyed school classrooms for children with special needs, and compared the performance of a sound-field and a portable public address system in classroom environments. Unoccupied room noise levels and reverberation times were measured in eight classrooms at four Hong Kong schools for children with special needs. Speech levels in each classroom were measured under three conditions: without amplification, with public address system amplification, and with sound-field amplification. Speech-to-noise ratios were calculated for each condition. Noise and unamplified speech-to-noise ratio values exceeded recommended acoustic standards in all classrooms. When sound-field and public address amplification systems were installed, speech-to-noise ratios improved considerably. When either amplification system was used, a uniform sound-field resulted. The applicability of both types of amplification system and their relative merits in special education classrooms are discussed.
[Copyright of International Journal of Disability, Development and Education is the property of Routledge. Full article may be available at the publisher's website:
http://dx.doi.org/10.1080/10349120600847508]