Acoustic effects of medical, cloth, and transparent face masks on speech signals

Ryan M Corey, Uriah Jones, Andrew C Singer, Ryan M Corey, Uriah Jones, Andrew C Singer

Abstract

Face masks muffle speech and make communication more difficult, especially for people with hearing loss. This study examines the acoustic attenuation caused by different face masks, including medical, cloth, and transparent masks, using a head-shaped loudspeaker and a live human talker. The results suggest that all masks attenuate frequencies above 1 kHz, that attenuation is greatest in front of the talker, and that there is substantial variation between mask types, especially cloth masks with different materials and weaves. Transparent masks have poor acoustic performance compared to both medical and cloth masks. Most masks have little effect on lapel microphones, suggesting that existing sound reinforcement and assistive listening systems may be effective for verbal communication with masks.

Figures

FIG. 1.
FIG. 1.
(Color online) Masks used in experiments and described in Table I.
FIG. 2.
FIG. 2.
(Color online) Speech signals were produced by a human talker and loudspeaker model. Microphones were placed at listener distance and at several points on and near the face.
FIG. 3.
FIG. 3.
(Color online) Effect of different masks on sound levels measured at the listener position for a head-shaped loudspeaker (left) and human talker (right). Human speech attenuation values are means over three recordings. The overall standard deviation between human recordings was between about 1 and 2 dB at the plotted frequencies.
FIG. 4.
FIG. 4.
(Color online) Spatial distribution of 2–16 kHz sound energy for a head-shaped loudspeaker with different masks in dB relative to no mask at 0 degrees.
FIG. 5.
FIG. 5.
(Color online) Effect of the PVC window mask (11) on sound levels measured at different microphones relative to the same measurements with no mask on a human talker.
FIG. 6.
FIG. 6.
(Color online) Effect of several masks on sound levels at a lapel microphone on a human talker relative to sound levels at the same microphone with no mask.

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Source: PubMed

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