The ongoing pandemic caused by the COVID-19 virus is challenging many aspects of daily life. Several personal protective devices have become essential in our lives. Face protections are mostly used in order to stop the air aerosol coming out of our mouths. Nevertheless, this fact may also have a negative effect on speech transmission both in outdoor and indoor spaces. After a severe lockdown, classes have now started again. The adoption of face protection by teachers is either recommended or mandatory even though this is affecting speech intelligibility and thus students’ comprehension. This study aims to understand how protections may affect the speech transmission in classrooms and how this could be influenced by the several typologies of face protections. An experimental campaign was conducted in a classroom in two different reverberant conditions, measuring and comparing the variation in speech transmission and sound pressure level at different receiver positions. Furthermore, a microphone array was used to investigate the distribution of the indoor sound field, depending on the sound source. Results clearly show how different types of personal protection equipment do affect speech transmission and sound pressure level especially at mid-high frequency and that the source emission lobes vary when wearing certain types of personal devices.

由 COVID-19 病毒引起的持续大流行正在挑战日常生活的许多方面。一些个人防护设备已成为我们生活中必不可少的。面部保护主要用于阻止空气气溶胶从我们的嘴里出来。然而，这一事实也可能对室外和室内空间的语音传输产生负面影响。经过严格的封锁后，现在又开始上课了。建议或强制要求教师佩戴面部保护装置，尽管这会影响语音清晰度，从而影响学生的理解力。本研究旨在了解保护措施如何影响教室中的语音传输，以及这如何受到几种面部保护类型的影响。在教室中的两种不同混响条件下进行了一项实验活动，测量和比较不同接收器位置的语音传输和声压级的变化。此外，还使用麦克风阵列来调查室内声场的分布，具体取决于声源。结果清楚地显示了不同类型的个人防护设备如何影响语音传输和声压级，尤其是在中高频，并且当佩戴某些类型的个人设备时，源发射波瓣会发生变化。