The Influence of Face Masks on Speech
The global pandemic of COVID-19 lead to mandatory face mask laws in many states of the EU, spawning a general conception that face masks alter speech intelligibility. In a two-part study we investigated the effect of three different face masks (FFP2, surgical and cloth mask) on acoustic features as well as intelligibility loss.Part one of the study involved the acoustic analysis of speech in different face mask conditions. Acoustic parameters that include harmonic relations (e.g., H1-H2), formant amplitudes (e.g., A1) and noise measures (e.g., harmonics to noise ratio (HNR)) were extracted from the data of one female and one male speaker. To control for intra-speaker variability, we built an artificial head-loudspeaker system adapted to the human voice to play the sound samples. The experiment was performed in a sound attenuated booth using two condenser microphones (AKG C451). In part two of this study a perception test was carried out to test the effect of the face masks on speech intelligibility.The statistical analyses of the first experiment revealed that sounds are affected most in higher frequency bands. The perception test showed that the intelligibility is affected by the masks albeit context may matter.