Hearing Protection - Bone Conducting Noise

[Oly]

For a little while I have been thinking about getting some Emtec moulded plugs - but I have been put off due to hearing/reading something about hearing loss through bone conductive processes. Bascially I was under the impression that you can still suffer from hearing loss if the bones behind your ear are not covered - as they are with traditional muffs.

 

I've been doing a little research tonight and come across this:

 

'A common myth concerning HPDs (hearing protection devices) is that as the sound level increases BC (bone conductive) sound becomes more important, and therefore an earmuff will provide better protection than an earplug at higher sound levels. The inaccuracy of this statement is demonstrated by the fact that the relationship between the AC (air condutive) and BC thresholds, as shown in Figure 2, is not dependent on sound level. Any BC advantage that muffs may have over inserts will be independent of sound level, and will be apparent in a standard threshold level attenuation test such as ANSI S3.19-1974.'

 

This was taken from the top of the third (right hand) column on page two of this document http://www.e-a-r.com/pdf/hearingcons/earlog5.pdf

 

So...as I may be being a little thick tonight ...does this mean that basically (as bone conductive noise occurs through all sorts of bones in the body and not just the ones directly behind your ear) it makes no difference whether you wear muffs or plugs??

[Chris-NZ]

For a little while I have been thinking about getting some Emtec moulded plugs - but I have been put off due to hearing/reading something about hearing loss through bone conductive processes. Bascially I was under the impression that you can still suffer from hearing loss if the bones behind your ear are not covered - as they are with traditional muffs.

....

 

 

All this bone conduction stuff is -totally- irrelevant.

There is a huge acoustic impedance mis-match between air and flesh, providing at least 50dB attenuation in most cases.

 

In reality, you need to provide adequate attenuation of the air-conducted signal. I'll warn you now- custom plug effectiveness is dependent on both the quality of ear impression -and- the skill of the plug manufacturer. High grade impressions (down past the second bend using a dam/no voids/adequate material viscosity/....) are the starting point but mistakes can still be made by the plug manufacturer. Plugs should feel firm in the ear without causing pressure points, and when you wiggle your ears, they should stay well sealed and not migrate about or break the sound seal.

 

If rifle shots still sound unpleasantly loud and/or you have tinnitus (ringing in the ears) after using any given protector, they're almost certainly providing inadequate protection

 

Chris-NZ

[col48]

Hi

i have just had a pair of pure tone ear plugs made and they are very very good. the noise enhancement is a bit of a put off if you have them turned up to loud,(as i did when i was out with the shot gun,at a busy shoot)

but on the hole I'm quit happy with mine,i think they are very expensive, but when you look at mods being £275 each and the plugs being £500 and i have had quit a few mods, but you will never be able to sell the ear plugs,as they are for you only,so i just hope they last a long time.

 

ATB

Colin

[Oly]

Cheers guys. It's so difficult to tell as it is a very technical/medical matter - and you don't want to be unprotected. I have thought about electronic muffs - but they hit the stock on my guns. Electronic plugs are a good idea - but they are still a lot of money, and the eltronic bit may go wrong I suppose - but I've been thinking for a while about a pair of Emtec plugs with a sonic valve in. Many have rated them highly and they are not far from me so I may give them a call soon.

[col48]

Cheers guys. It's so difficult to tell as it is a very technical/medical matter - and you don't want to be unprotected. I have thought about electronic muffs - but they hit the stock on my guns. Electronic plugs are a good idea - but they are still a lot of money, and the eltronic bit may go wrong I suppose - but I've been thinking for a while about a pair of Emtec plugs with a sonic valve in. Many have rated them highly and they are not far from me so I may give them a call soon.

 

 

Hi

when i brought my pure tones i asked about what if they go wrong,and can i get/ pay for insurance, they said list them on your house insurance and they will be covered,i asked can i pay for them to be serviced every year,he said just keep using them and if / or when they go wrong they only charge £40 to repair them no mater what is wrong with them.

 

ATB

Colin

[kip270]

For a little while I have been thinking about getting some Emtec moulded plugs - but I have been put off due to hearing/reading something about hearing loss through bone conductive processes. Bascially I was under the impression that you can still suffer from hearing loss if the bones behind your ear are not covered - as they are with traditional muffs.

 

I've been doing a little research tonight and come across this:

 

'A common myth concerning HPDs (hearing protection devices) is that as the sound level increases BC (bone conductive) sound becomes more important, and therefore an earmuff will provide better protection than an earplug at higher sound levels. The inaccuracy of this statement is demonstrated by the fact that the relationship between the AC (air condutive) and BC thresholds, as shown in Figure 2, is not dependent on sound level. Any BC advantage that muffs may have over inserts will be independent of sound level, and will be apparent in a standard threshold level attenuation test such as ANSI S3.19-1974.'

 

This was taken from the top of the third (right hand) column on page two of this document http://www.e-a-r.com/pdf/hearingcons/earlog5.pdf

 

So...as I may be being a little thick tonight ...does this mean that basically (as bone conductive noise occurs through all sorts of bones in the body and not just the ones directly behind your ear) it makes no difference whether you wear muffs or plugs??

 

 

You won't regret getting these, i have had mine for 5 years

 

 

 

[Chris-NZ]

....Electronic plugs are a good idea - but they are still a lot of money, and the eltronic bit may go wrong I suppose -....

 

 

The two predominant causes of these dying is putting them away damp, and secondly not being careful enough to keep wax out of the receiver outlet. When you're finished with them, I suggest open the battery drawer fully and leave them to ventilate for a day before storing them. Wipe the shell over with a tissue after removing them but cleaning the receiver outlet of wax is best done later when any wax will be dry and crack off easily.

 

It's very unusual for the electronics themselves to die but external mechanical stuff like the microphone(s) are definitely less robust.

 

Chris-NZ

[Oly]

To be honest the electronic ones are a bit too pricey for me at the moment. Plus the bonus of not having to worry about them has got to be quite a plus for me! Emtec will no doubt do the job for a fair while, and when they don't anymore maybe I'll reevaluate the cost of electronic ones!

 

Many thanks

[Trapper]

I've had Puretones for nearly three years and am very happy with them. All the cost is in having the moulds made and the units made from them.

I probably put in two battery sets a year but thats only pence.

There's a clever device for trapping ear wax that needs cleaning sometimes but otherwise thats it.

I reckon, if written off over five years, it will be well worth the money.

[Wsm]

Col/Trapper

 

What price would the PureTones be ?

[Trapper]

No idea what current prices are but I suggest the following ned to be priced in:

 

Vist to practice nurse to get your ears syringed and de-waxed

Visit to a Turkish Barber in North London to get your outer earhole hair flamed out during haircut.

Visit to ear specialist in Harley Street to get moulds made or similar, Puretone will tell you nearest specialist.

They will send moulds to Puretone

 

Demo here:

http://www.censdigital.com/

[Chris-NZ]

No idea what current prices are but I suggest the following ned to be priced in:

 

Vist to practice nurse to get your ears syringed and de-waxed

Visit to a Turkish Barber in North London to get your outer earhole hair flamed out during haircut.

Visit to ear specialist in Harley Street to get moulds made or similar,...

 

 

 

Might be a bit of over-kill there (excuse the pun)

 

An audiologist has a 95% chance of taking impressions from cold without pre-syringing. As for de-hairing, if they can't clip out what's there on the spot, you're in the top 1% of the population for "gorilla lugs" Almost never an issue.

 

Just make sure you get an experienced/qualified person to take the impressions.

 

good luck

Chris-NZ

[col48]

Col/Trapper

 

What price would the PureTones be ?

 

 

hi Tim

 

went for the top of the range ones to finish up, they where £500

i had my molds done at the midland game fair,and paid £400 there then up graded about a week later,thought i might as well have the best, i deserve a treat every now and again

o and the guess what i brought, the same day i got myself a wildcat mod sometimes you just get caught up in the moment.

 

ATB

Colin