Carl C. Crandell, Gary W. Siebein , M. Joyce Hasell, Martin A. Gold
Phillip Abbott, Christopher Herr, Hee Won Lee, Mitchell Lehde
University of Florida
P.O. Box 115702
Gainesville, FL 32611-5702
Presented Tuesday afternoon, June 17, 1997
133rd ASA Meeting, State College, PA
Numerous investigations (see Crandell, Smaldino and Flexer (1995) and Nabelek & Nabelek (1994) for reviews) have demonstrated that the acoustical environment in a classroom is an important variable contributing to the academic achievement of children with normal hearing and children with hearing impairment. For example, the acoustical environment of a classroom has been identified as a critical factor in the psychoeducational and psychosocial achievement of children with hearing impairment. Specifically, inappropriate levels of classroom noise and/or reverberation have been shown to deleteriously affect not only speech perception, but also reading/spelling ability, behavior, attention, concentration, and academic achievement in children with even minimal degrees of sensorineural hearing loss (SNHL) (e.g., ASHA, 1995; Crandell, 1991, Crandell & Bess, 1986, Crandell, Smaldino, & Flexer,1995; FinitzoHieber & Tillman, 1978; Ross, 1978).
Additional data have isolated a number of populations of children with normal-hearing sensitivity who experience greater speech perception difficulties in the classroom environment than has traditionally been suspected (Crandell, Smaldino, & Flexer, 1995; Nabelek & Nabelek, 1994). These "normal-hearing" populations include young children (<13-15 years' old); children for whom English is a second language; children with developmental delays and/or attention deficits; and children with articulation, language, and/or learning disabilities.
With these considerations in mind, the purpose of the present investigation was to examine the relations between teaching methods, speech-recognition measures, acoustical measurements, and the architectural design features of classrooms. Data obtained will be used to develop appropriate classroom acoustics for elementary school children. Specifically, the following methods were followed:
Participatory Action Research (PAR) is a form of Whyte's (1991) "participatory action research" (PAR) was used to identify communication, learning, teaching, architectural and acoustical issues from the perspectives of the teachers and students. This approach is widely used in the appraisal of qualitative aspects of environments to assist in programming new facilities and post occupancy evaluation of existing buildings. It was hypothesized that the complex interactions among the physical environment of the classrooms, the teaching techniques of the faculty, the behavior of the students, and the quality of the learning that occurs in the rooms can be identified using these methods. Once the broad range of issues were identified, a series of case studies were conducted in actual elementary schools to gather the data for the present project.
Room and Student Selection
Once the major issues were identified through the PAR studies, a series of rooms and students were evaluated for case studies. Initially, the study focused on 3 groups: Pre-kindergarten to grade 1, grades 2-3, and grades 4-6. Further studies will include middle school, high school; and college students as well as adults. Children were initially selected and screened for normal hearing. Follow-up work will address these issues relative to the special populations noted above.
Schools were chosen to gain representative samples of different socioeconomic classes, races, and genders in the students. The classrooms were chosen in several localities including urban, suburban and rural areas. Buildings constructed at different times in different conditions with different acoustical qualities were also chosen.
A series of acoustical measurements were made at multiple locations in each class room from multiple source locations using the impulse response technique. A TEF analyzer, JBL's Smart system and two custom systems were available for this work. Acoustical measures of reverberation time, early reverberation time, early to late energy ratios, loudness (or relative strength), Alcons, speech transmission index, background noise levels and signal-to-noise ratios as well as binaural measures were made to document the acoustical conditions. In addition, the architectural features such as dimensions, volume, seat locations, materials, shape, furnishings, etc., were recorded in detail.
Speech recognition tests
Speech recognition of children in the rooms was assessed by nonsense syllables and monosyllabic word tests. The stimuli were presented in the classroom via a calibrated digital tape recorder through a loudspeaker that closely approximates the directional characteristics of the human voice. The source was placed at the front of the classroom and at other locations identified in the PAR studies where the teacher might frequently stand. Monosyllabic nonsense stimuli were used because: (1) practice/learning effects are minimal; (2) children as young as 5 years of age can perform this task; (3)closed set testing responses can be utilized; and (4) consonant confusion matrices can be produced from the data. The child's task was to circle the correct choice on an answer sheet. On each speech-recognition form, the location/position of the child in the room (distance from the speaker, position in the classroom, etc.) was documented.
Learning qualities tests
A survey instrument and participatory action techniques were used to assess acoustic and non-acoustic factors that might affect speech recognition and learning.
Relations among the teaching methods, speech recognition measures, acoustical measurements, and the architectural design features of the classrooms are currently being analyzed. These data will be presented in detail at the Acoustical Society of America annual conference in State College, Pennsylvania.
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Crandell, C. (1991). Classroom acoustics for normal-hearing children. Implications for rehabilitation. "Educational Audiology Monographs", 2(l), 18-38. (back to top)
Crandell, C., & Bess, F. (1986). Speech recognition of children in a "typical" classroom setting. "American Speech-Language and Hearing Association", 29, 87. (back to top)
Crandell, C., Smaldino, J., & Flexer, C. (1995). "Sound Field FM Amplification: Theory and Practical Applications". Singular Press: Los Angeles, CA. (back to top)
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