The impact of face masks on spectral acoustics of speech: Effect of clear and loud speech styles.

This study quantified the effects of face masks on spectral speech acoustics in healthy talkers using habitual, loud, and clear speaking styles. Harvard sentence lists were read aloud by 17 healthy talkers in each of the 3 speech styles without wearing a mask, when wearing a surgical mask, and when wearing a KN95 mask. Outcome measures included speech intensity, spectral moments, and spectral tilt and energy in mid-range frequencies which were measured at the utterance level. Masks were associated with alterations in spectral density characteristics consistent with a low-pass filtering effect, although the effect sizes varied. Larger effects were observed for center of gravity and spectral variability (in habitual speech) and spectral tilt (across all speech styles). KN95 masks demonstrated a greater effect on speech acoustics than surgical masks. The overall pattern of the changes in speech acoustics was consistent across all three speech styles. Loud speech, followed by clear speech, was effective in remediating the filtering effects of the masks compared to habitual speech.