Factors affecting the quality of sound recording for speech and voice analysis

The importance and utility of objective evidence-based measurement of the voice is well documented. Therefore, greater consideration needs to be given to the factors that influence the quality of voice and speech recordings. This manuscript aims to bring together the many features that affect acoustically acquired voice and speech. Specifically, the paper considers the practical requirements of individual speech acquisition configurations through examining issues relating to hardware, software and microphone selection, the impact of environmental noise, analogue to digital conversion and file format as well as the acoustic measures resulting from varying levels of signal integrity. The type of recording environment required by a user is often dictated by a variety of clinical and experimental needs, including: the acoustic measures being investigated; portability of equipment; an individual's budget; and the expertise of the user. As the quality of recorded signals is influenced by many factors, awareness of these issues is essential. This paper aims to highlight the importance of these methodological considerations to those previously uninitiated with voice and speech acoustics. With current technology, the highest quality recording would be made using a stand-alone hard disc recorder, an independent mixer to attenuate the incoming signal, and insulated wiring combined with a high quality microphone in an anechoic chamber or sound treated room.