I came across an interesting hearing protection product at this year’s National Hardware Show – Decibullz’ custom-molded ear plugs. Before I get into the details, let’s talk a little about ear plugs in general.
Ear plugs and earphones sold as hearing protection must be tested and given a noise reduction rating (NRR). If you see hearing protection products without an NRR rating, such as cheap non-branded foam ear plugs at a big box store, they might not protect your hearing as well as you think.
The NRR indicates how many decibels (dB) of sound are attenuated by the device. The higher the NRR, the better. Most ear plugs fall between a NRR of 24 and 32 dB.
You might not think that is a very great difference, but the dB scale is logarithmic, so an increase of 3dB equates to a doubling of sound. Subject your ears to too much sound over a long enough period of time and your hearing can be permanently damaged.
It’s worth noting that the highest possible NRR for any ear plug would be in the neighborhood of 35dB. That’s because you could block 100% of the sound entering through your ear canals and some would still get “in” through your teeth and bones. Chew something crunchy with your ears plugged and you’ll see what I mean.
Ear plugs custom-molded to fit the wearer’s ear canals are at the high end of the spectrum, in terms of effectiveness and comfort. Originally, the only way to get them was to go to a specialist who could mold them on-site or take an impression and ship custom-made plugs later on.
More recently, it became possible to mold them yourself by mixing a two-part silicone compound and molding it to your ear canal and outer ear.
Decibullz‘ ear plugs offer something different, a heat-activated material (thermoplastic) that can be softened by immersion in hot water. The material is attached to a stem that accepts a variety of in-the-ear plugs (provided). When the material is heated, you insert the plug and mold the material to fit the outer part of your ear.
Here’s a video showing how it all works:
Unlike other custom-molded plugs, these can be immersed again in hot water and reshaped for a better or more comfortable fit. Properly fit, Decibullz have a NRR of 31 dB, which is about as good as it gets for in-the-ear plugs.
Decibullz offers several products based on this custom molding technology. There are regular ear plugs which provide the mentioned hearing protection, and also earphones that can be connected by Bluetooth or wire to a media device. The earphones are intended to provide audio and do not offer any rated hearing protection.
Decibullz also offers percussive filters, which allow you to hear normal sounds but selectively block sound from guns, artillery, and other percussive sounds. They do this by means of a tiny “valve” that instantly closes when subject to high sound pressure.
I asked an engineer at Decibullz how the mechanism works and he likened it to covering the end of a toilet paper tube with an index card and having the wind blow against it. The stronger the wind, the tighter the seal between card and tube. The same is true of sound pressure; the higher the percussive sound the tighter the “valve” seals. Additional sound dampening is provided by a series of acoustic mesh filters.
Percussive filters do not receive an NRR rating because it’s not a relevant measure of the protection provided by this kind of device. NRR is the average protection at all frequencies; percussive filters only protect against rapid sound spikes at certain frequencies. I was told they should provide protection for people using nail guns and jack hammers, but not for something like a concrete saw, which produces a solid wave of sound.
The percussive filters are “developed for shooting and military use”; it would be wise to contact Decibullz before using them for other applications.
Connected to a phone or other media device, the wired and Bluetooth plugs can be used to listen to audio or make and receive calls. The wire coming out from the plugs also contains a microphone and a module that allows you to control your phone or media device (on/off, volume, skip songs, make or take phone calls, etc.).
Decibullz does NOT currently offer dB-limiting earphones. Earphones with this feature limit would audio to 85 dB or less, which is the maximum 8-hour exposure allowed by OSHA. If you use Decibullz’ earphones or any others that don’t offer dB limiting, be sure not to blast the audio or you could end up damaging your hearing.
- Ear plugs: $26
- Wired earphones: $40-60 ($60 for the latest generation)
- Bluetooth earphones: $120
- Percussive shooting filters: $75
More Info(via Decibullz)
I stumbled across this company while wandering the exhibition hall at the National Hardware Show. I’ve never used custom-molded plugs, but can see how Decibullz’s would likely provide a higher level of protection. After all, they have the type of in-the-ear plug I already wear, plus a secondary seal from the molded material.
Stuart’s Note: From what I’ve seen, there are some disposable foam ear plugs that provide a comparable level of protection, but foam ear plugs can be more difficult to insert than reusable ones. Reusable ear plugs, such as those by 3M/Peltor, have a noise reduction rating of 26 dB.
Ideally, anyone who works in loud environments would wear custom-molded plugs produced by an industrial hygienist. But for reasons of cost and convenience, that’s unlikely to happen.
DIY molded plugs like the ones from Decibullz are a reasonable second-best choice. I like the idea of being able to mold plugs myself and remold them if I’m unhappy with the initial fit.
There are a couple of caveats to owning these plugs. It’s important to follow the instructions when molding them—especially as relates to the heat of the water and allowing the material to cool slightly before shaping to your ears. And you don’t want to store molded plugs where they might get hot enough to lose their shape.
It doesn’t matter if you choose to wear custom-molded ear plugs, traditional foam or reusable ear plugs, or earmuffs – what does matter is that you wear some kind of protection when working with tools that operate at hearing-damaging levels.
If you know anyone who suffers from Tinnitus or some other kind of hearing damage you’ll understand how miserable and debilitating it can be. Hearing damage is permanent; once it’s gone, it’s gone; hearing damage is permanent.
2 years ago, we asked you about your favorite hearing protection, and only one reader mentioned wearing custom molded ear plugs.
How many of you wear custom-molded ear plugs now? How many of you are open to the idea?