Use of digitized speech materials in audiological research

Computer methods, based on the theory and application of signal processing, combined with numerical methods for simulating mathematical processes, facilitate greater objectivity in most aspects of speech intelligibility testing, including specification of the stimuli, control of the tests, evaluation of the responses, corrective feedback, and automatic interpretation. This paper discusses several basic issues in digital signal processing, and also describes the application of computer-aided procedures for recording and delivery of speech materials for audiologic research. Examples of the use of computer procedures for manipulation of digitized stimuli demonstrate the increased efficiency and versatility of these procedures compared to more conventional tape recording methods. In addition, the use of digitized recordings allows more reliable specification of speech levels than conventional calibration methods involving observations of signal peaks on a VU-meter.