Canadian Consulting Engineer

Professor at UBC develops tool for modelling classroom acoustics

According to acoustics experts, children with normal hearing may hear only 75% of the words spoken by a teacher. Pr...

May 3, 2004   Canadian Consulting Engineer

According to acoustics experts, children with normal hearing may hear only 75% of the words spoken by a teacher. Professor Murray Hodgson at the University of British Columbia is developing a tool to help.
A noise level of 40 to 60 decibels, rather than the recommended level of 35 decibels, is often prevalent in classrooms, he says.
Hodgson has rated the acoustical quality of every UBC classroom and found excessive levels of reverberation in many of them. “The vast majority are sub-par,” he says.
Existing tools for designing acoustics are expensive and not available to the non-specialist, says Hodgson, whose work is conducted under the auspices of the Centre for Health and Environmental Research in collaboration with the Department of Mechanical Engineering. He wanted to develop an accessible software package at a reasonable cost: the result is ClassTalk, the first hardware/software system of its kind in the world.
ClassTalk models the sound-absorbing features of a room such as acoustical treatments, carpets, seats and the people in the space, and the noise outputs of sources such as the heating and ventilation system, multi-media equipment, and student activity.”Designers forget that students absorb sound. If you have a large classroom with 300 students that may be enough absorption — you don’t need anymore,” says Hodgson. ClassTalk measures four voice levels and reverberation at seven frequencies and allows the user to walk around a room while a teacher is talking. It can be used for new designs or retrofits.
In Canada, unlike in Europe, “it is not very common for engineers to ever learn anything about acoustics,” says Hodgson, who teaches engineering graduate students and an elective course to 4th year students at UBC. “Engineers need to appreciate the acoustical environment is an important aspect of life that affects people in many different ways, and that they can control it by engineering design and maybe they should include it more in their education systems.” Demonstration versions are available at:

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