Quality evaluation of microphones used for lecture captures in universities

Recently, lecture capture has become progressively more important to Higher Education institutions. They allow automated recordings of lectures to be taken and stored for consumption by remote students or students who wish to revise the class. The technology involved has become increasingly complex and hence the need to independently assess the quality of recordings made by the microphones. This paper describes a recent series of experiments carried out with microphones commonly used for the live recording of lectures in university teaching rooms. Two laboratory-based experiments were designed to compare the audio recordings from the microphones; using nine Audio Visual engineers, that currently assess the perceived quality of lecture capture at universities. The ratings of the recordings were captured on a five-point mean opinion scale (MOS). Two different approaches to recording were followed, i.e. using simultaneous recording and substitution. Results were analysed by correlation to investigate if there is a significant relationship between the measurements of each of the six microphones, when compared to results from a class 1 sound level meter, and the quality rating by the engineers.