Acoustic Effects of Face Masks on Speech: Impulse Response Measurements Between Two Head and Torso Simulators

Victoria Anderson – vranderson@unomaha.edu
Lily Wang – lilywang@unl.edu
Chris Stecker – cstecker@spatialhearing.org
University of Nebraska Lincoln at the Omaha Campus
1110 S 67th Street
Omaha, Nebraska

Popular version of paper 4aAA10
Presented Thursday morning, December 2nd, 2021
181st ASA Meeting,

Due to the COVID-19 Pandemic, masks that cover both the mouth and nose have been used to reduce the spread of illness. While they are effective at preventing the transmission of COVID, they have also had a noticeable impact on communication. Many find it difficult to understand a speaker if they are wearing a mask. Masks effect the sound level and direction of speech, and if they are opaque, can block visual cues that help in understanding speech. There are many studies that explore the effect face masks have on understanding speech. The purpose of this project was to begin assembling a database of the effect that common face masks have on impulse responses from one head and torso simulator (HATS) to another. Impulse response is the measurement of sound radiating out from a source and how it bounces through a space. The resulting impulse response data can be used by researchers to simulate masked verbal communication scenarios.
To see how the masks specifically effect the impulse response, all measurements were taken in an anechoic chamber so no reverberant noise would be included in the impulse response measurement. The measurements were taken with one HATS in the middle of the chamber to be used as the source, and another HATS placed at varying distances to act as the receiver. The mouth of the source HATS was covered with various face masks: paper, cloth, N95, nano, and face shield. These were put on individually and in combination with a face shield to get a wider range of potential masked combinations that would reasonably occur in real life. The receiver HATS took measurements at 90° and 45° from the source, at distances of 6’ and 8’. A sine sweep, which is a signal that changes frequency over a set amount of time, was played to determine the impulse response of each masked condition at every location. The receiver HATS measured the impulse response in both right and left ears, and the software used to produce the sine sweep was used to analyze and store the measurement data. This data will be available for use in simulated communication scenarios to better portray how sound would behave in a space when coming from a masked speaker.

 

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