Thread: Ozito electronic earmuffs

Hey People Listen To Groggy he hit the nail right on the head. I have been a shooter for 35+ years, just becuase they sound ok when you are wearing them does not mean they are protecting your hearing. Hearing protection is a complicated sience remember once it's gone it's gone.

Confusion reigns

I don't disagree that we should always be sure that our safety gear is up to scratch, and I'm not endorsing any product, but I think Groggy and others are endowing the cheap Ozito earmuffs with technology that just is not there!

These are not active noise cancelling headphones, they are earmuffs with a microphone. They are nothing like the Bose units, or any of the active stuff available for pilots or shooters.

Here's the Ozito Link:
http://www.ozito.com.au/prodtype.asp...prodtypeid=260

They claim >85db attenuation, and SLC80 rating: 22, Class 4, for AUS/NZ, Test standard: AS/NZS 1270:2002

The Bose website makes no db claims for their products that I can find. The specifications link mentions the size and weight of the headphones. Same for the Pilot product. They do say say things like:

Slip on a pair of QuietComfort 2 headphones and hear your music come alive. Decades of Bose research combine with our Acoustic Noise Cancelling headphone technology for outstanding audio performance. This award-winning technology electronically identifies and dramatically reduces noise while faithfully preserving the music, movie dialogue or tranquility you desire.

Acoustic Noise Cancelling® Headphone Technology

Standard headphones are designed only to deliver audio and not intended for use in loud environments. They do little to fade background distractions.
The patented Acoustic Noise Cancelling® headphone technology in Bose® QuietComfort® 2 headphones provides full-spectrum noise reduction for a better audio experience. Microphones in the earcups actively monitor what you hear, including unwanted outside sound. The difference between the unwanted sound and the desired sound is then electronically processed, creating a correction signal that acts to negate the unwanted noise. The speaker within each earcup is then fed the correction signal. This signal, combined with the passive noise reduction of the headset itself, dramatically reduces the outside noise that reaches your ears.

http://www.bose.com/controller?event...adphones_index


Note that everything they are comparing them against mentions headphones, not earmuffs. These are not safety items...



I don't have anything extremely noisy in my workshop (the DC is the loudest) and I do have a selection of earmuffs, all of which reduce the racket to very bearable levels, including the ozito's (still without batteries).

woodbe

What a great discussion! I had assumed ANR technology, a poor assumption as it turns out, and thanks to woodbe for pointing that out.

Lets not lose the message in the detail though, the wearers' hearing needs to be protected, first and foremost. The use of specific frequency boosting to allow the wearer to hear voice ranges better, or ANR style technology really doesn't matter to the point I was making. That being, do they actually protect your hearing?

The SLC80 rating of 22 sent me off to research a bit, and I found an old article written by a friend of mine who was then in a job related to aviation ground safety (I dont think it appropriate to post the detail but am willing to provide a link to anyone who wishes to verify the data).

In the short article, it mentions current approved earplugs have an SLC80 ratings of 24db to 28db. Approved earmuffs have SLC ratings up to 32db and can be used in environments that include weapon ranges.

But what does this mean? Well, I am not sure, and this is why I would rather a health professional commented because it gets technical. The SLC calculation involves averaging results from a test group across a range of set frequencies. The averages result in the dB rating provided. However, it is possible the muff is particularly effective at one end of the spectrum (low) but offer virtually no protection at the other. But, because it is averaged, it comes out sounding ok. Now, if you work in an environment that is rich in the 'open' frequency, you could be unprotected but not know it.

Countering this is the class 4 rating of the Ozito muff, which sounds pretty good. What I am cynical of though, is the cost vs the claim of effectiveness, it just doesn't sound right. In a way, it is like the American 110v 6HP Sears Shop Vac. To the uninitiated it sounds good, and it certainly sucks up a storm. To the electrical tradespeople it is laughable. Still, the manufacturer can claim it 'legally'. Similarly, I suspect the claims of this device but do not have the knowledge to examine it fully (this is unfair, I agree, to accuse without facts to support it. However I've said it to indicate why I am curious about their claims. Is it a case of too good to be true, or, is it my distrust of a brand I have had problems with previously clouding my judgement - you decide for yourself).

SLC = sound level conversion, the 80 means it should apply to 80% of the population if it is correctly worn.

As a matter of interest, angle grinders are recommended to be used with a hearing protection device with a SLC80 rating of 30-32.

The Ozito link states it "Attenuates noise >85db". I wish I understood what that meant. Over 80dB (I think) is where you need protection. Does this mean it only reduces sound if it exceeds 85dB? If so, there is an unexplained discrepancy. Or, does it mean it reduces all noise by 85dB? Or does it attenuate certain frequencies only by 85%? Or perhaps anything over 85dB is not retransmitted by the speakers?

There are a lot of such issues associated with hearing protection, and I keep going back to I'd really like some objective professional opinion. Forget the fact it's Ozito we are talking about, whatever the brand, I think hearing protection is very poorly understood and too often we may buy something that simply does not do the job for a woodworker.

If anyone has access to an environmental health expert - please ask them to chime in!

I believe its 85db is the cutoff for safe noise exposure (well it used to be anyway).

I have a certificate I in public health from years back when doing my uni course (its probably called something else now), but admittedly, I never used it for anything. Anyway, during the course the lecturer exposed us to 85db sound for about 5 mins. I can tell you that it was loud!

Very few of my tools seem to come close to this level of noise (except maybe the miter saw) but I still think it is less. I'd imagine you would have to put your ear pretty darn close to the motor to be exposed to greater than 85db, but your tools may be different, so don't take that as gospel

The Ozito link states it "Attenuates noise >85db". I wish I understand what tat meant. Over 80dB (I think) is where you need protection. Does this mean it only reduces sound if it exceeds 85dB? If so, there is an unexplained discrepancy.

Well, "attenuate" means to become weaker in strength, value, or magnitude, so when it says it attenuates noise greater than 85db, I guess it means it reduces the strength, value, or magnitude of the noise above that 85db limit, hence reducing it to 85db (the safe exposure limit) or to a lower level (dependant on the strength of the original noise emission... I guess if your original source is 120db and your earmuffs only reduce it by 22 or 25 decibels, you are still going to be over the "recommended" safe limit.

I'd go out on a limb here and say that as casual woodworkers, and assuming you wear some form of ear protection with a half decent rating, your exposure to noise and resulting damage would be on the minimal side compared to other professions where exposure to much larger db sources are frequent and/or continuous. That's just an opinion of course.

Jesus boys, we're in the realms of rocket science.

Seems to me that the bottom line is that for $30 you get some earmuffs that let you hear normal conversation a bit better than normal earmuffs (which is all 95% of us weekend hackers wear)

I, for one, next time I clip on my Lear Jet harness, or fire up my Tiger Moth, or grab the handles of my pnuematic hammer will not look for hearing protection in Bumblies or Mitre 9.5 @ $29.95!

Chill

Originally Posted by Bodgy

Jesus boys, we're in the realms of rocket science.

Seems to me that the bottom line is that for $30 you get some earmuffs that let you hear normal conversation a bit better than normal earmuffs (which is all 95% of us weekend hackers wear)

I, for one, next time I clip on my Lear Jet harness, or fire up my Tiger Moth, or grab the handles of my pnuematic hammer will not look for hearing protection in Bumblies or Mitre 9.5 @ $29.95!

Chill

The bottom line is your hearing, and the discussion is an attempt to learn something. What is wrong with exploring this that bothers you?

I think that sound levels are actually significantly higher than 85 in my workshop. Rush hour traffic is around 102, and dust extractor and saw together are easily another step up the scale from that.

Greg

Originally Posted by Groggy

The bottom line is your hearing, and the discussion is an attempt to learn something. What is wrong with exploring this that bothers you?

Don't bother me sweetie, go for it.

Originally Posted by Dean

I'd go out on a limb here and say that as casual woodworkers, and assuming you wear some form of ear protection with a half decent rating, your exposure to noise and resulting damage would be on the minimal side compared to other professions where exposure to much larger db sources are frequent and/or continuous. That's just an opinion of course.

And an educated opinion, I am not questioning your judgement or comments.

How do we measure value for money from these things? If we were discussing a hand plane worth the same amount we could go on for an eternity about the year it was made, who made it, the steel used, does it have certain markings, how much meat is left on the blade etc. For electrical tools we can measure cut quality, smoothness of operation and a host of other factors that include tool life.

It doesn't take an extended period of time to hurt your hearing. If your ears are ringing after doing something - that's damage. How do I know if they are any good medically.

(I added a bit more to the post questioning attenuation, I understand the meaning of the word, but not the context they intended)