Gear Review: SureFire EP4 Sonic Defenders

If you read the TTAG About Us page – and you know you should – then you know that I’m currently wrapping up my Master’s Degree in Environmental Management. After working for the past 6 years as a chemist in the semiconductor research and development world, my career will be making a drastic switch this spring when I change career paths. Using my chemistry and HVM (high-volume manufacturing) experience, I will focus on hazardous waste and hazardous material management. I also intend to become heavily involved (i.e. CIH certified) in industrial hygiene and worker safety. With that in mind, you can take my word that I get excited about things like ear plugs. Seriously, I do…

Nothing gets me more hot and bothered like NRR ratings, N/P/R classifications, and HEPA filters. OK, so maybe not really hot and bothered, but I certainly appreciate a great fitting, reusable, hypoallergenic ear plug with noise blocking technology. Enter the SUREFIRE Earpro EP4 Sonic Defenders.

Since I’ve been shooting my ARs and rifles more, I’ve been looking for a set of ear plugs to use in place of my Howard Leight Impact Sport ear muffs. Don’t get me wrong – I love my Impact Sports. I even recommended them in my 2011 Holiday Gift Guide. They have served me well in pistol competitions for the last two years.  The issue I am having with the Impact Sports is they won’t stay on my ears when shouldering a long arm, particularly ones with Monte Carlo style stocks.

Boring background info…

Regardless of what some may say, ear plugs are not idiot proof. In the IH (industrial hygiene) world, this type of misconception doesn’t just apply to ear plugs, but rather all types of PPE (personal protective equipment). Many workers and hobbyists are prone to the mistaken belief that all types of PPE are inherently easy to use and are always 100% correctly donned. Well, six semesters of a Master’s program and six years experience says otherwise.

Needless to say, when the Big Brown Truck dropped off the EP4s I was eager to see how they fit and functioned. Having never liked those cylindrical disposable foam plugs (the make my ears itchy after just a few minutes), I always favored the newer “tripled-flanged” style made of silicon-rubber or similar polymer.

One of the major attractions of the Sonic Defenders is that they offer the same triple-flange design that I prefer and are also made from a soft, comfortable, hypoallergenic medical-grade polymer. The added benefit of the Sonic Defenders is that they incorporate something known as a “Hocks Noise Braker”.

The Noise Braker is based on the physics axiom that energy as we know it cannot be created nor destroyed; it is simply just converted to another state. The Noise Braker inside the Sonic Defenders protects your hearing by converting sonic energy into thermal energy by means of compression and acceleration. Of course, you’ll never notice the rise in temperature, but you will constantly be protected from dangerously high noise levels.

At the range…

I had to adjust the earpieces after wearing them for a few minutes. Apparently, my ears are “short” (albeit large) and the cones were extending too deeply into my ear canal. Adjusting the earpiece and stem is done by simply pushing in or pulling out the stem to a comfortable length. After a quick push, the fit was perfect.

I tested the EP4s on the same day that I tested my Remington 700 XCL TLR. I found the EP4s comfortable, easy to put on (in?), and very effective. During the trip, temperatures reached 70 degrees (don’t you just love Phoenix in January!) and my ears didn’t get itchy or irritated – even after four hours of testing. During some of the cease-fires, I did take the EP4s out to let my ears air out and found they were easy to remove and reinsert even while walking back and forth from range bench to target stand.

The Noise Brakers proved to work flawlessly. There were a few silhouette shooters practicing at the same time I was and let me just say, those big pistols can be quite loud. We also had multiple long gun shooters come and go, including a gentlemen shooting his new Christmas gift – a .338 RUM.


The Sonic Defenders come in two styles: the standard EP3 model (16dB NRR) and EP4 Plus with enhanced noise reduction (19dB NRR). Both models can be used with radio communicators, although I don’t have the required equipment to test how well that works. For those who want more “permanent” ear protection, you can insert the stopper into the opening of the Noise Brake and receive a constant 24NRR.

While I’m at it, I have one more side note about NRR ratings. NRR ratings are determined by monitoring noise attenuation across a broad spectrum of sound frequencies and then taking into account a “safety factor.” If you’re bored or afflicted with insomnia, feel free to give the CDC website a once-over.  What this means is that the NRR is a single number (e.g. 16NRR, 19NRR, 24NRR, etc) designed to give users a reliable assessment of how much hearing protection they can expect from a product.

The problem with this rating system and testing method is that they rely on continuous noise sources for calculations. Unfortunately, it may not be an accurate indicator of protection attainable against loud impulse noises. Like gun fire. SureFire has conducted independent testing and found the EP4 Sonic Defenders to be effective in helping to protect against impulse and continuous noise sources.

The size of the Sonic Defenders required is related to the size of your conchal bowl. Yes, you have one, too.  It’s the smaller “c” of your ear and the one directly connected to the ear canal opening. I had to use the “large” size because my ears rival those of a basset hound. SureFire says that the majority of users will be able to use the standard size plugs. The triple-flange canal piece will adjust to fit all sizes of ear canal openings so those remain the same regardless of what size you use.

SureFire states that the life expentancy of the Sonic Defender’s is 3 to 6 months. After using mine, I wiped them down with a bit of rubbing alcohol (as I do with all my PPE) to disinfect. Once dry, I put them back in the included plastic case (don’t throw it away) and put them back in my range bag for next time.

It’s generally understood that noise-induced hearing loss starts at pressure levels of 85 db when exposed to for long periods of time (such as an 8-hr work day), and that noises greater than 140 dB (120 dB for children) will cause some sort of hearing loss. These minute losses add up over time and lead to hearing impairment. The last I checked, a shot fired from a .30-06 registers somewhere above 160 dB. So be smart, use ear protection all the time and not just at the gun range, OK?

Ratings (Out of Five Stars)

Ergonomics: * * * *
While not as simple to use as ear muffs, the Sonic Defenders are easy to insert and fit comfortably, even after hours of use.

Ease of Use: * * * *
Unpack, insert, verify fit, and you’re good to go. Wipe down with a mild soap and water or some alcohol wipes and you’re set for next time.

Overall Rating: * * * *
Get em’ and use em’… while you’re at it, stop using sun glasses and make sure you get real safety glasses for your next trip to the range.