TOKYO--(BUSINESS WIRE)--The Laboratory of Hearing Cognition of universal sound design inc. (hereafter “LHC,” HQ: Minato-ku, Tokyo, Japan, President and CEO: Shinichiro Nakaishi), a company aiming to create, through R&D on its high-resolution Sonic Brain® acoustic technologies, a society universally capable of hearing, has performed a joint survey with the Tokyo Metropolitan Industrial Technology Research Institute (hereafter, “TIRI”) on Speech Damping Due to Tools for Preventing Droplet-Based Infection.
The purpose of the study was to understand the difficulties present in hearing when using masks, face shields, acrylic barriers, etc., to prevent the spread of COVID-19. This was accomplished by analyzing differences in sound pressure levels when masks, face shields, acrylic barriers, etc., were used and were not used. The results of the survey showed marked damping in frequency bands that affect hearing of consonants when an acrylic barrier was used, and, when a face shield was used, there was an unnatural amplification of the middle register and a decrease in speech clarity.
Measurements & Methods
Audio playback: Broadband noise played through mouth simulator (speaker) placed in mouth of a mannequin (HATS)
Measurements: Measurements made by microphone placed at entrance to ear canal of right ear of listener
Frequency analysis method: One-third octave band analysis
Evaluation method: Evaluation of differences in sound pressure from results of using acrylic barriers to prevent droplet-based infection, masks, and face shields compared with control
*Control: nothing is worn by speaker and no acrylic barrier is used.
With regard to these results, Dr. Masafumi Nakagawa (Professor, International University of Health and Welfare) commented that:
“A damping of 5db is observed at 2000Hz and above when only a mask is worn. This means that the power behind consonant sounds like “t,” “sh,” and “h” is halved, which in turn means that a listener may not hear a consonant or be unable to differentiate between words like “he” and “she.”
“Shields cause similar damping at 2000Hz, but also have an amplifying effect at 800 to 1500Hz. We tend to think that increased volume is a good thing, but if a vowel’s second formant (f2) is emphasized, it can make it more difficult to differentiate between vowels.
“Wearing both a shield and a mask reduces clarity of consonants and the unnatural emphasis of a vowel’s second formant (f2) can lead to mistakes in hearing sounds like “ha” and “a” and being unable to differentiate between “he” and “she.” Being unable to hear consonants makes it difficult to hear numbers, and this can create problems at checkout because the listener needs to pay attention to the display on the register and is unable to communicate with the shop staff, which should instead be one reason to enjoy shopping.
“The maximum damping effect is 10dB, which means that if you use familiar words, speak slowly, enunciate, etc., you can still minimize any discrepancies even when wearing a mask or shield.
“Coronavirus was initially thought to have been transmitted via droplets, but we are now hearing from recent research that measures against aerosols are also necessary. This makes frequent ventilation necessary when using masks and shields, and seeing people for longer than 15 minutes should be avoided.”
The difficulty in hearing caused by the use of masks, face shields, and barriers is of an even greater level for people with difficulty hearing and hearing impairments. Being unable to hear increases stress and a sense of isolation, and so now it is important to think about communication support and systems that can enable anyone to hear.
comuoon® tabletop communication support system
comuoon® is a tabletop communication support system that achieves a new paradigm for conversation support by allowing the speaker, not the listener, to improve how well their speech can be heard. Instead of focusing on the issues facing existing devices like hearing aids that place the burden of accommodation on the listener, comuoon® instead converts what the speaker says into something much easier for the listener to hear and understand, making for improved conversation.
Frequency bands that affect speech clarity are understood to be those at 1,000Hz and above. comuoon® utilizes its proprietary speaker and innovative construction to provide improved fidelity between 1,000 and 10,000Hz.
The benefits of comuoon® in speech discrimination for hearing impaired were presented from a neuroscientific standpoint at the 14th Annual World Congress of Brain Mapping and Therapeutics and the 118th Annual Meeting of the ORL Society of Japan, where it was explained that clarity, not volume, is necessary when speaking with a person with a hearing impairment. comuoon® can be used not only as a tool to help the hearing impaired, but also as a tool for hearing rehabilitation.
Laboratory of Hearing Cognition, universal sound design inc.
The Laboratory of Hearing Cognition conducts research on the effects of super-high resolution sound technologies on the human body.
Collaborative research on the effects of super-high resolution sound on the human body has been performed with a variety of universities, including Kyushu University, as well as other laboratories, medical facilities, and nursing facilities. The Laboratory also developed Sonic Brain®, a technology that makes it easier for the brain to understand speech. The Laboratory is currently involved in hearing frailty awareness through its Hearing Cognition Check app that helps visualize the user’s cognitive abilities to hear words and helps check for early-stage hearing loss.