FACE MASKS AND SPEECH RECOGNITION
Jun 30, 2020
William Eagen, Church Council VP at St. Peter’s Evangelical Lutheran Church, Huntington Station
After attending the “MNYS Reopening” webinar I found the information very enlightening and comforting, and it went a long way to help me focus on a starting point and provided valuable direction on how we will need to proceed as we plan to reopen our worship space.
I would like to share my experience/expertise in terms of how we should communicate while wearing facemasks. I am a retired Speech-Language Pathologist and Audiologist and, while I am no longer practicing my profession(s), I try to maintain a certain level of current knowledge. One issue that has arisen in educational audiology is the impact of facemasks on speech reception. This is an important issue, not only for the hearing impaired population, but for anyone trying to clearly discern a spoken message through a facemask.
Recent studies have demonstrated that the typical cloth (and plastic as well) facemask acts as a low pass filter below 2kHz, effectively reducing the higher frequencies that are critical for meaningful speech reception. Depending on the material and fitting of the mask, the high frequencies can be reduced anywhere between 4dB and 12dB. While these numbers appear small, the reduction can have the effect of making the signal virtually unintelligible for anyone with even a mild hearing loss (think anyone over 50 whether they admit it or not). Add into the equation any significant distance, the acoustics of virtually any large space (pulpit/church/auditorium/classroom), background noise and the result is that the ability of any listener to hear a clear signal is severely hampered (did I hear “call the apostle or Paul the apostle?). The use of microphones and amplifiers can/do often compound the problem for a variety of reasons.
So, how do we present an intelligible speech signal in this new age of the facemask? Contrary to our instinctive reaction, louder is not better. The lower frequencies are powerful (think of a diesel engine) whereas the high frequencies are weak (think of a bird’s chirp). Raising the voice and speaking louder only amplifies those low frequencies even more, masking out the critical high frequencies necessary for speech clarity (try listening to that chirping bird as a garbage truck drives past). Ergo, how should one speak through a facemask? We need to slow down a smidge, and enunciate. A typical, rapid, conversational speech rate reduces the familiarity and redundancy that is built into our language sharing. By slowing down, only slightly, we can improve the reception of the speech signal significantly. How do we do that? The simple answer is for the speaker to concentrate on pronouncing every sound as she/he speaks. The act of trying to pronounce every sound will automatically reduce the rate, while maintaining the rate necessary to allow for the continuity of the message without being distracting. This takes some practice, but it really isn’t difficult, and the results can be dramatic in terms of speech reception for listeners. The average person isn’t going to do this. But, perhaps, clergy can learn how to do it as they try to project the Word through their facemasks. Just a long-winded thought… I know everyone has bigger fish to fry right now, but wanted to share my concern while it was fresh in my mind.