The study found that disposable surgical masks offer the best acoustic performance among all tested, Corey said. Loosely woven 100% cotton masks also perform well but, as shown in a study by other Illinois researchers, they may not be as effective as surgical masks at blocking respiratory droplets. That study showed that tightly woven cotton and blended fabrics may block more droplets, but Corey’s team found that they also block more sound. Based on the droplet study, Corey suggested that multilayer masks made of loosely woven cotton may offer a reasonable compromise between droplet-blocking efficiency and acoustic performance.
The good news is that most masks do not completely block sound, they simply deflect it away from the mouth. This detail means that simple amplification devices can make masked speech more accessible to everyone. In particular, the lapel microphones that are already used in many classrooms and lecture halls are only mildly affected by face masks. Many hearing aids support remote microphone accessories that are also worn near the lapel.
The results of the team’s new study evaluating the acoustic effects of face masks on speech are published in The Journal of the Acoustical Society of America.
Release date: 23 December 2020
Source: University of Illinois