1 April 2021
There’s no need to shout
As the general public grapples with the mild annoyance of sometimes having to wear a facemask, medical professionals are long familiar with the downsides of PPE – such as difficulties communicating with patients, especially those with existing hearing loss.
Boffins at Sydney University’s Voice Research Laboratory have taken a deep dive into exactly how a person’s voice changes when they are wearing a mask and how this affects how well they are understood.
The study compared acoustic voice measures of 16 adults with and without two different mask types: the three-layer surgical mask that fits loosely over the nose, mouth and chin and the KN95 filtering respirator mask that fits more tightly to the face.
And the key finding is, the intuitive response of speaking more loudly when wearing a mask will not usually improve how the speaker is comprehended, mainly because the face covering does not make the voice softer overall.
Instead, it is the tendency of masks to muffle or distort the sound of our consonants that causes the problem, and the KN95s are worse than the surgical masks in this regard, the study finds.
“We found that masks affected mostly the sounds with higher frequency energy above 1000 kilohertz which is generally related to the transmission of consonants, not so much vowels,” Associate Professor Cate Madill, Director of the Voice Research Laboratory, said.
“This is likely because we use our voice to produce vowels sounds such as ‘a’ or ‘e’ but it is air turbulence and not the vocal cords that produce ‘voiceless consonants’ such as ‘p’,‘t’, ‘k’, ‘f’, ‘s’ and ‘sh’,” she said.
“So speaking louder is unlikely to improve how a person is understood when wearing a mask and could in fact lead to vocal fatigue.”
But if speaking up is not the answer, what is? It transpires that mask wearers could learn a trick or two from the thespian community.
As any ham worth their salt will tell you, “hyperarticulating” is the key to getting the message across. What that means in practical terms is: speak more slowly, use more pauses and only up the decibel level as a last resort.
To paraphrase theB, “the quality of clarity is not strained …”
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