New Earplugs Won\u2019t Amplify the Sound of Your Own Voice<\/p>\n
Wearing earplugs, hearing aids and earphones can make your own voice sound booming, but a new design dampens the din<\/p>\n<\/div>\n
By Rachel Berkowitz<\/a><\/p>\n Typical earplugs can make the wearer’s own voice sound booming.<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n If you plug your ears, the voices around you become muffled\u2014while yours becomes annoyingly amplified<\/a>. \u201cIt\u2019s like talking with your head in a barrel. Your own voice sounds booming,\u201d says K\u00e9vin Carillo, an engineer who specializes in acoustics and vibration at \u00c9cole de Technologie Sup\u00e9rieure in Montreal.<\/p>\n This \u201cocclusion effect\u201d can make devices such as earplugs and hearing aids <\/a>uncomfortable, and it sometimes dissuades people from using them at all. Now Carillo and his colleagues have created a 3D-printed earplug that dampens these bothersome internal noises, they reported earlier this month<\/a> at a meeting of the Acoustical Society of America.<\/p>\n When earplugs, earbuds or hearings aids block, or \u201cocclude,\u201d the outer ear canals, they create closed cavities<\/a> between themselves and the eardrums. In these cavities, the low-frequency sound waves we routinely make by speaking, chewing and breathing, which propagate through the body\u2019s tissues and bone, will resonate and become amplified before hitting our eardrums.<\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing<\/a>. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n Previous solutions to this problem tended to be inefficient, uncomfortable or expensive. Researchers had tried developing ventilated earplugs that allow some air to pass through, custom-made plugs that fit deeper into the ear canal and devices that rely on active electronics to cancel out the low-frequency sound. But Carillo and his colleagues wanted to find a simpler, lower-cost approach. The team 3D-printed tiny interconnected cavities filled with energy-absorbing foam and attached them to a standard earbud-style insert. The low-frequency sound waves in the ear canal enter these cavities and bounce around. By tailoring the cavities\u2019 size and shape, the researchers were able to create a resonant structure that traps and dampens such sound waves instead of amplifying them.<\/p>\n![\"Yellow](\"https:\/\/static.scientificamerican.com\/dam\/m\/28f3907d58ed437b\/original\/GettyImages-1501191787_WEB.jpg?w=600\")
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