ɪn nˈaɪntiːnhˈʌndɹɪd ˈeɪɾi ɐ dᵻɹˈɛkʃənəl mˈaɪkɹəfˌoʊn wʌz ˌɪntɹədˈuːst ɪnðə dˈɪdʒɪɾəl hˈɪɹɪŋ ˈeɪd, ænd ɐdˈæptɪv fˈiːdbæk kˌænsɪlˈeɪʃən wʌz kɹiːˈeɪɾᵻd tə blˈɑːk ɛkstˈɜːnəl nˈɔɪz ðætðə mˈaɪkɹəfˌoʊn pˈɪkt ˈʌp.
In 1980 a directional microphone was introduced in the digital hearing aid, and adaptive feedback cancellation was created to block external noise that the microphone picked up.