Glancing at the article, this seems like a baroque approach to a problem with a much more elegant solution.
I’m a professional musician and audio engineer and for years I’ve been using custom earplugs that I acquired through a visit to an audiologist. They took an impression of my ear canals and within a week provided molded custom-fit plugs. These plugs provide passive attenuation spec’ed to my preference (-15dB, -20dB, -30dB, etc) and they do so in a way that attenuates evenly across the frequency spectrum, rather than over-attenuate the high frequencies like foam earplugs do, so that you don’t experience muffled sound. They’re comfy and work flawlessly. I’ve never taken them out due to discomfort.
I’m a professional musician and audio engineer and for years I’ve been using custom earplugs that I acquired through a visit to an audiologist. They took an impression of my ear canals and within a week provided molded custom-fit plugs. These plugs provide passive attenuation spec’ed to my preference (-15dB, -20dB, -30dB, etc) and they do so in a way that attenuates evenly across the frequency spectrum, rather than over-attenuate the high frequencies like foam earplugs do, so that you don’t experience muffled sound. They’re comfy and work flawlessly. I’ve never taken them out due to discomfort.