Center for the Built Environment

Small conference rooms are often used for either face-to-face communication or for virtual meetings involving an electroacoustical link between a talker and a listener. The intelligibility of speech in such environments depends on a number of factors, one of which is the nature of the reverberant sound within the space. Treating such a room with sound-absorbing materials helps reduce the so-called “cognitive load” for people who are spaced some distance away from a talker or who are listening to monaural speech reproduced by a loudspeaker. This study describes an acoustical retrofit of a small conference room to attain the reverberation time criterion found in LEED version 4.1 ID+C. Several mathematical models were used to predict the reverberation time before and after adding soundabsorbing treatment. In addition, measurements were conducted to quantify the before and after room reverberation characteristics. We found that speech was always intelligible both before and after the retrofit; however, one’s cognitive load is noticeably reduced when listening to speech after installation of the treatment.