How do you know when loud noise is too loud when wearing noise cancelling headphones?

I use an industrial zero turn mower that will compete with helicopters in noise level. I have always used the foam type ear plugs with no know problems. I recently had to get Bose hearphones to help with my hearing so I tried them while mowing and they seemed to cancel the noise very well. But…for the second time I’ve mowed I’m noticing my hearing is not as good after, especially the next day. I’m not sure if this is coincidence or not (we did have a weather change last night) or if the noise is getting to my ears and I just don’t know it. I did try earmuffs over the hearphones and it seemed to make a roaring sound so I didn’t use them…

I did have a procedure performed a couple weeks ago and my ears are changing daily anyway but mostly for the better.

Hey Tim, long time no chat! I hope the new devices are working out for you.

How much attenuation do the Bose devices give you without turning on the noise cancellation functionality? This might help you figure out if the temporary threshold shift is associated with your lawn mower (which sounds like it’s awesome!) or the music coming through your headphones.

Hey Alvin, yeah I’ve been having a rough stretch the past few weeks. The procedure went well but left me in a way I couldn’t understand spoken word even with HAs. Gradually getting better. Not a good time to be trialing HAs. My Audi is going to extend the 45 trial though. I’ve cancel two appointments with her because we both agreed with would be pointless to adjust aids with my hearing changing daily.

Sorry I can’t answer your questions about the hearphones, a little over my head. I just know when I mute them all outside sound is gone but to a normal hearing person the mower noise might be something to be concerned about.

As a military helicopter pilot in the 70s, I sure hope your mower is nowhere near as loud as the UH-1N helicopter I flew. They are noisy, either inside or out, and long term exposure leads to hearing loss for many. I always wore earplugs inside my helmet and I still had loss when I left the service. However, back in the 70s the military wasn’t that careful about noise exposure and the USAF jet pilot helmets we used didn’t provide as much hearing protection as the Army and Navy helicopter specific helmets from the same era.

A current helicopter headset has significant passive noise reduction that may be enhanced by electronic noise reduction. For example a David Clark H10-76XL military type headset provides 24 dB of passive noise reduction (NRR). The electronic noise reduction provides 17-22 dB beyond the passive. The headset is large and fits over your ears sealing against your head - that helps with the passive reduction.

Finding specifications for Bose equipment isn’t quite as easy, especially for consumer level equipment. Quickly looking at the Bose page for the hearphones, I don’t find a specification for the noise reduction, either passive or active. In any case, I doubt that your Bose hearphones provide the noise reduction of a quality aviation headset, especially those for helicopters or loud general aviation (unpressurized) aircraft.

You might consider wearing industrial type noise reduction muffs when using your mower. You might be able to wear you HAs inside the muffs (I wear mine inside some large headphones that provide 20+ dB of passive noise reduction). If the HAs are MFI or bluetooth, you could possibly hear your phone or streaming music with high NRR muffs.

I hope your hearing stabilizes and you find a solution to the noisy mower.

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This mask thing actually has opened up my eyes and many others about how much we depend on lip reading. Your trial during the coronavirus might actually prove the hearing aids in a better fashion.???

I have a grasshopper diesel zero turn, it is really loud but nothing like GE frame 5 and 7 gas turbines I worked around for years. There are a bunch of us on this forum who worked around some very noisy conditions. I am afraid that is why we are here.

I got off topic, sorry.

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No, there’s no way. Although I’ve never heard a helicopter up close, I have heard them fly over pretty low and they sound awesome. I have a nephew that fly’s for the Navy. On one if his training exercises he flew over my business on his way to a Naval base. The whole family was there watching and waiving as he circled around us. It was so awesome. With my weird hearing I could hear the low deep tone of the copter coming way before anyone else.

I did try wearing the large ear protector headgear over the Bose and I couldn’t tell it made any difference. In fact it created a slight roar.

Thanks for your suggestions

So I guess my question is, are we still damaging our hearing even while wearing protection?

Another question, are noise canceling headphones as good regular ear protection (foam plugs rated at SNR 34db or large ear muffs)?

When you do the math on dB noise with any hearing protection devices the answer is pretty straight forward.

Using your 34 dB noise reduction ear plugs in a 120 dB environment equates to a 86 dB environment with those hearing devices. I believe the standard for damaging ears starts at 85 dB. So, for the most part your properly fit 34 dB ear plugs in a 120 dB environment could be used pretty much all day without damaging your hearing.

Just guessing, a commercial zero turn is probably around 110-120 dB.

Is this the type answer you are looking for?

I’d be careful regarding the noise reduction provided by hearing protection ratings. Looking at NIOSH, I found this:

“Finally, regarding hearing protection, NIOSH indicated that the noise reduction rating (NRR), a single-number, laboratory-derived rating that the U.S. Environmental Protection Agency (EPA) requires to be shown on the label of each hearing protector sold in the United States is not adequate. In calculating the noise exposure to the wearer of a hearing protector at work, NIOSH recommends derating the NRR by subtracting from the NRR 25%, 50%, and 70% for earmuffs, formable earplugs, and all other earplugs, respectively.”


A significant issue with earplugs is fit - many people don’t fit or put earplugs in correctly and then they don’t work as well as the rating would imply. Muffs also have issues (sealing, etc) but apparently are somewhat more likely to perform closer to their NRR rating. Tim noticing a roar with muffs over the Bose possibly indicates the lack of a good seal.

The best solution would be for manufacturers of noisy equipment to work to (significantly) reduce the noise generated. Better mufflers, better blade design, quieter engines, and reducing the vibration of parts would help. Harder to do with a helicopter when every pound of silencing cuts a pound of fuel or load capacity but not so hard with a mower :slight_smile:

Ok, if the rating is correct and we properly fit the protection, we can calculate if we are good to go or not. The Bose ratings we do not know and that is kinda the reason for this thread.

Next question, while using Bose noise canceling, if you cannot hear the loud noise (mower) does that mean your okay?

OK, here’s a question. I find that when I remove my hearing aids, my hearing level is almost non-existant. So what I have been doing is simply removing my hearing aids and then I mow! That may be a faulty thought process as I have been told that just because I can no longer hear the full blast of my mower engine, does not mean I am having damage done to my ear drums by loud noise that I am too deaf to hear. Do you think there is any truth to this?

I happened to remember I have a Radio Shack SLM from back in the day I had to setup my sound system. I dug it out and checked my mower. It varied from 98db to 103db. My Audi said to bring the Bose in and she will check it’s noise level reduction.