On the Hock page, their “test data” consisted of two correspondences from research labs with a few comments and numbers. One of those letters showed the attentuation rate coupled with the input sound, and that could be where the NRR claims originate.

I’m hesitant to call BS because the plugs seems to be based off a (forgive the pun) sound principle. On the other hand, where’s the 3rd party stamp of approval, and why hadn’t larger companies (aside from Surefire) pick up on the idea…

The more time I spend looking into this, the worse it all smells. It’s just a stepped canal whose miraculous properties were only measured by its eponymous designer? No patents, no papers, nothing like an explanation? I’m calling it pseudoscience until I hear otherwise.

I can’t seem to find info as to whether or not it is OSHA approved or otherwise.

Here’s a nice flash animation about how the Hocks barrier is supposed to work.
http://www.noisebrakers.com/howitworks.php

I have a set of shooter’s earplugs, which are for impulse noise only — they only work on a single positive pressure front. The diaphragm relies on a pressure difference to seal itself, so sustained loud noise won’t activate the mechanism. They’re good for shooting and not much else.

Incodentally, the super-soft foam plugs are Hearos brand, and I think I got them at Rockler.

ALSO - http://www.surefire.com/pdfs/EP3_tech_copy.pdf

http://www.surefire.com/maxexp/main/co_disp/displ/prrfnbr/24306/sesent/00/EP3-Sonic-Defendersandtrade

They allow you to hear regular voices/sounds but they basically gate everything above 80 db per their claims. No electronics.

I prefer “cans” for general nuisance noise like compressed air and occasional grinding work, because they don’t take any time to don or doff, and don’t require clean hands to do so. My favorite pair is a folding set that nestles against each other when stowed in a toolbox, so they stay reasonably clean. (Keeping them in a bag is a good idea anyway, and if you sew yourself a bag from a big microfiber cloth, you can turn it inside-out and use the clean surface to wipe off your glasses.)

For prolonged or more serious noise exposure like shooting or hammerdrill work, I’ll wear some canal plugs under the cans. The typical foam plugs are uncomfortably stiff, but I recently found some ultra-soft ones that advertise the same NRR, and frankly even if they’re not as good, wearing them is better than not wearing the stuff ones. (I’ll post a brand name when I find ‘em..)

Also worth a look (or a listen!) are the rubber plugs that look like a pagoda, or a succession of mushrooms. A little research reveals that they’re called “flanged earplugs”. Like cans, they go in instantly and don’t require clean fingers, but like foam plugs they’re pocket-sized and cheap. I don’t use them much because they’re a bit uncomfortable, but I keep a pair in my toolbag just in case.

There’s an impressive selection at The Earplug Store: http://earplugstore.stores.yahoo.net/

For the geeky: Peltor makes some (very expensive!) electronic headset hearing protectors that include Bluetooth transceivers, so you can pair ‘em to your phone, music player, laptop, or whatever. Even cooler is the adapter that makes your two-way radio speak Bluetooth, so you can skip the annoying headset cord. I haven’t had a chance to test them out, but I’m so glad someone finally put these two good ideas together.

1) The NRR on any hearing protection is a fun number for ad copy, but in real-world use, you can expect about half the NRR advertised.

If you’re in an environment that subjects you to 100 dB of noise on a regular basis, in other words, wearing 30-dB cans or plugs will get you to about 85 dB in the ear, which is the level at which OSHA requires employers to provide (and employees to *use*) hearing protection. In other words, if your job site is this loud, wear multiple types of hearing protection.

Which brings me to rule of thumb #2: the NRRs are not additive, but wearing plugs under cans is a lot better than either one by itself.

Another thing to be aware of: lots of people do not use plugs properly. Foam plugs like the ones pictured must be rolled into a small cylinder, then carefully inserted into the ear and allowed to expand. If you don’t roll them tight and can’t get at least 75% of the plug into your ear, you didn’t do it right and you aren’t getting anywhere near the protection you think you are. Headphone-style cans are a better option for a lot of people because they’re fairly foolproof — put them on and you’re (fairly well) protected without any fuss.

I spend an average of about 90 hours each month in the cockpit of a turboprop-powered airliner, and I wear both foam plugs *and* a headset. That gets the noise level down to where I can tolerate it most of the time, although I’ve been known to turn on the active noise reduction on the headset on long flight legs. Plugs by themselves are OK, but the headset by itself is not really enough protection for my taste.

If you find that the cheap foam plugs don’t seem to fit all that well, you might try using your other hand to *gently* lift up on the top of your ear before inserting; this straightens the ear canal somewhat and makes it easier to get the plug in to its full depth. Also, I find that sometimes I haven’t compressed the foam part enough to get in all the way.

Of course, I’m sure that I just reiterated the instructions printed on the back of the package, but I’ve had to show enough people how to put plugs in over the years that I think it bears repeating.

http://www.amazon.com/EP412-Each-Quattro-Corded-Plugs/dp/B0007LRQ9A
http://www.amazon.com/Plugs-Hearing-Protection-Shooting-Hunting/dp/B000RB391Y

They are more useful b/c you can take them out to talk w/someone, then put them back in to continue working. The foam ear plugs didn’t like being reused that often through the day.

Another advantage of ear plugs versus ear muffs is they’ll fit under your welding helmet