Acoustical scale modeling in the classroom at MIT

Abstract

This is an actual demonstration of the acoustical scale modeling methods that have been used by the author for several years to help teach some basic acoustics to students in two classes at the Department of Architecture. One class in the curriculum of Building Technology, instructed by Cad Rosenberg of BBN, uses scale modeling to show how the reverberant sound within an interior space forms from numerous wall reflections. Echograms from various model room configurations illustrate simple defects that may occur in the quality of the interior sound. Also, students see demonstrated clearly the difference between the reduction of noise by surface absorption and by transmission loss. Another course attended by equal numbers of undergraduate and graduate students is instructed by Tim Johnson and John Furlong. It explores various aspects of the microclimate. One part, acoustics, is presented in the form of one lecture and a brief acoustical scale modeling demonstration immediately followed by a laboratory activity in which students investigate the control of sound from a highway into a nearby community. Students use the scale modeling instrumentation to help select the appropriate noise barrier that will give an acceptable community noise level, or/and noise reduction, at the lowest cost. There is no one solution to the problem, but students must show their understanding of acoustics by justifying their selection quantitatively.