Page 13 - Summer 2007

decision to look for an immediate remedy. President Eliot asked the twenty-seven year old Sabine, who had just received his assistant professorship, to address the acoustics with (in Sabine’s words): “...the end in view of correcting the lecture-room which had been found impractical and aban- doned as unusable.” 7
Sabine’s analysis of the lecture room is best described in his 1898 presentation8 and in the numerous letters published in W. D. Orcutt’s 1933 biography of Sabine.9 Samples of his hand-written notes from his tests in the lecture room have also been published.10 Sabine’s work provides the foundation for the science of room acoustics.
In addition to the difficulties of teaching by day and acoustic testing between 2:00 a.m. and 6:00 a.m., when the Harvard Square streetcars were not running, Sabine was under pressure from President Eliot to provide a solution for the lecture room, his initial task:
“Your explanation of November 3rd about your expendi- tures in making the investigation which Mr. Hooper and I asked you to make is very far from being satisfactory. You have made sufficient progress to be able to prescribe for the Fogg Lecture Hall, and you are going to make that prescription.” 9
Eventually Sabine prescribed acoustic treatment for the Lecture Room, stating that the room was “...not excellent, but entirely serviceable...without serious complaint.”11 Why his opinion was not shared by others is not clear, but in 1911-12 the lecture room was reduced from over 400 seats to around 200. In the words of the museum director: “We hope for a... roof that does not leak (and) a medium-sized lecture hall instead of a large one in which you cannot hear.” 12
No records have been found on the lecture room from the 1911-12 remodeling to 1927 when the new Fogg Art Museum was opened and the old building became an annex to the school of architecture. However, the drawings for the remodeling showed a new inner semi-circular wall following the column line with no sound absorbing material. This inadvertently restored the rear wall echo that Sabine had pre- viously removed.
In 1935, the year that the Faculty of Design was estab- lished, the building was renamed Hunt Hall in honor of its architect. Around this time a layer of hair felt covered by a perforated asbestos board was installed on the lower two- thirds of the inner wall. Little additional information prior to 1965, when the room was first carpeted, could be elicited either from available documents or former occupants.
In 1972 the museum was returned to the Fine Arts fac- ulty and some inexpensive changes were made to the lecture room. On the recommendation of Professor Robert Newman, a flat canopy was added over the raised lecturer’s platform and an eight foot high band of highly absorptive material was added around the semi-circular inner wall. In 1973 a student report described the acoustical changes in the following manner: Before remodeling, focused reflections from walls and ceiling created locations at which “...the sound was reinforced making hearing very easy (assuming the speaker did not move). Conversely there were dead spots where hearing was often extremely difficult.” After the remodeling, the student report concluded that “Having attended two class-
es a week since these corrections were made, I can say that the hearing conditions ... have been drastically improved. A speak- er anywhere to the front of the room can be heard clearly throughout the hall.” 13
The building was demolished in 1973 to make way for a student dormitory. So, for at least its final year, speech intel- ligibility in the room seemed to be relatively acceptable.
Acquisition of information
Acoustic reconstruction of an historical building, espe- cially one that is no longer standing, begins with the accu- mulation of documentation concerning not only the geome- try but also the construction materials. The documents found describing this room span 75 years, covering the series of renovations. Documents include original publications by Sabine himself, various architectural drawings, photographs, and several acoustical measurements.
Sabine’s papers
In Sabine’s important work, “Reverberation,” the Fogg
11
His drawing is reproduced here in Fig. 1. In addition to the drawing, a number of acoustical and construction details are given, summarized in Table 1. Subsequent to the fundamental research efforts in the room, establishing the relationship between absorption and reverberation time (first in terms of theatre seating cushions, then in terms of open window area) the room was modified from its original design through the addition of an absorbing material. According to Sabine, “...hair-felt one inch in thickness was glued to the walls in the rectangular spaces between the windows and on the recessed lunettes in the ceiling. Over this was stretched asbestos cloth, also of moder- ately high absorbing power...The asbestos was placed in con- tact with the felt, and held against it by an office-wire grating. The use of this construction was immediately successful, and it has remained untouched, the lecture room being used con- stantly, not merely for classes, but for public lectures and musi-
cal concerts.” 9
Art Museum was introduced.
Fig. 1. Lecture-room, Fogg Art Museum.11
Fogg Art Museum 11