The study of quality reception of audio signals in auditoriums is relevant because this fact determines the user's Quality of Experience (QoE). This paper presents experimental results regarding to the impact of the linear phase variations on the voice quality index. Speech files are played using different phases, and each audio transmitted is individually saved. Later, the original and the transmitted speech files are compared using a voice quality assessment metric. Experimental results demonstrate that the phase-angle is highly correlated with the voice quality index; therefore, a relation function between the angle and the quality index is proposed.