Towards an Objective Model of the Conversational Speech Quality

This paper proposes an approach to model the conversational speech quality and an optimisation of this approach to some practical cases. A new subjective test has been designed to study the relationship between conversational speech quality and talking, listening and interaction qualities, when facing echo and delay. The results show that, in these conditions of degradation, the subjective conversational mean opinion scores (MOS) given by subjects can be estimated from the talking and listening quality scores by a multiple linear regression, which coefficients are calculated to minimize the mean squared error (MSE) between subjective and estimated conversational scores. We show the validity of the proposed method in predicting the conversational quality scores for the conditions assessed in this subjective test. For this, a comparison between subjective and estimated conversational quality scores is performed, by means of correlation coefficient and mean absolute error