Hearing aid using an emphasized speech for hearing-impaired subjects
Hidenobu Harasaki, Shinji Ozawa, Hiroshi Ono, Toshisada Deguchi · The Journal of the Acoustical Society of America · 1983
A new hearing aid which emphasizes the phonetic features of monosyllables is suggested in this paper. In vowel parts of speech, we applied a digital filtering technique to a formant emphasis. The 101 order transversal filter emphasizes formant frequencies (+ 10 − + 30 dB). This filter enabled us to reduce misrecognitions of /i/ and /e/, /u/ and /o/ for hearing-impaired children. To emphasize consonant parts, three emphasis methods are experimented and discussed. One is an emphasis of amplitudes in consonant part, the next is a duration expansion of nasal consonant, and the last is an insertion of silence between stop consonants and the following vowels. The combinations of these methods were also experimented. The results of these experiments showed a distinct improvement in the recognition ratio of monosyllables.