2015 BFY II Abstract Detail Page
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||Study of Acoustics in Classrooms
||Acoustic evaluation studies of our University classrooms are currently being carried out. Classroom teaching has been one of the ancient form of education i.e., through oral communications. The quality of this communication and ultimately the classroom itself depends on the acoustic quality of the classroom. The acoustic quality can be characterized based on reverberation time (RT), sound insulation and noise levels. Reverberation time is the time taken for a steady state sound to reach one millionth or -60 dB of its original intensity. Low frequency noise along with background or noises from HVAC systems tends to have a detrimental effect of masking the lecture. An acoustically comfortable environment should be the one that provides everyone, individually and collectively, with the proper conditions to develop their learning skills. The acoustics of a classroom can affect speaker's intelligibility, mood, student concentration and in general the overall effectiveness in teaching and learning.
Reverberations in classrooms will continue till the sound energy is totally absorbed. RT in a class room depends on the quality and effectiveness of the sound absorbing enclosed surfaces. The fibrous ceiling tiles of a room provide enough friction for sound waves thereby absorbing more sound energy. RT for a typical class room ideally should be < 0.6s. At this University, almost all of our students have to undergo a year of English preparation and their vocabulary is highly limited. The sound quality of classroom instructions is of paramount importance. International standards recommend that the sound field amplification using electronics may greatly improve word recognition or requires that the instructor is within 6 - 8 feet of the students.
In this experiment, wherein one generates (ping source) a fixed sound and measures its loudness or sound pressure level (SPL) with a microphone as it being moved away from the source. The sound intensity (I) is different to the sound intensity level (L), which is the perceived sound intensity taking the response of human ear into account. The response of the ear to different intensities at fixed sound frequency is close to logarithmic. SPL measurements using Pasco sound sensors and Data Studio software was performed in classrooms which seem to have high degree of echo. A typical class room is box shaped with plaster walls, plaster board ceiling and linoleum finished floors. It has large glass windows with no curtains and one room has about 70 % of the wall surface is made of glass. Early studies indicate that low frequency sound of 500Hz is above 60dB. SPL measurements in dB for 1/3 octave frequencies will be done using a free dB meter based on ipad apps. From the collected data reverberation time for RT (30dB) will be determined for each of our classrooms and suitable wall coverings will be tried to bring them to the internationally recommended levels, which will be presented at the conference.
Dr Ramalingam P.
American University of Iraq, Sulaimani
AMERICAN UNIV OF IRAQ, SULAIMANI
Hazhy Rozh , UG student ( Engineering Major)
American University of Iraq, Sulaimani.