This paper was attempted to measure the S/N, at 15 classrooms of preschools and elementary schools for the deaf children, which are located in Seoul and Inchon. The data were obtained from December, 1999 to March, 2000. The S/N was measured at each distance of 1 m, 2 m and 4 m from the teachers by both dB (A) scale and dBSPL scale with one octave band width from 125 Hz to 8,000 Hz. The results were as follows:1) The S/N at the center frequencies of 500 Hz, 1,000 Hz and 2,000 Hz, important in the recognition of speech, was above +15 dB in the classrooms of 4 schools except one open school. 2) The distance from the teachers and children did not have significant effects on the S/N. 3) The environmental noise around the deaf schools did not give an influence on the S/N of the classrooms. 4) The numerical values of dBSPL scale were almost 10 dB higher than those of dB (A) scale in the low frequency
area below 500 Hz.
KEY WORDS:Signal·Noise