Why doubling-up hearing pro only gains you ~5dB

[gryghin]

Every once in a while the Surefire Sonic Defenders go on sale a Walmart. That's where I bought them for the whole family.

When I went to Clackamas County Public Safety Center last week, they said that ear muff style ear pro had to be worn because of the bone conduction of sound is more amplified indoors in a closed environment.

 

[Camelfilter]

Every once in a while the Surefire Sonic Defenders go on sale a Walmart. That's where I bought them for the whole family.

When I went to Clackamas County Public Safety Center last week, they said that ear muff style ear pro had to be worn because of the bone conduction of sound is more amplified indoors in a closed environment.

We like those surefires, but also double them up with electronic muffs for both music and command/conversation.

 

[SnapShot]

[*]The decibel scale is logarithmic. A change of ~3dB means a sound is either twice as loud or half as loud, depending. So, 23dB is twice as loud as 20dB, and 137dB is half as loud as 140dB.
[/LIST]

that is not entirely correct. Yes is it a logarithmic equation, you would be correct if you said a 3db change is either twice or half of the required power output to a speaker (it takes from say an amplifier) but the perceived loudness of a 3db change is minor - basicily the a 3db change is only just just barley noticeable - one might say turn it up a little --- and when you notice the change in perceived loudness thats about 3db.

in the case of increasing dB

dB change of 3 = 1.4x Volts = Power output (amplifier) 2x = perceived loudness 1.23x

to actually double perceived loudness it would be 10dB (again its a logarithm)
so in the case of 35db protection against 25 dB -- 35 will be 2x as much protection

here is a more detailed description of dB / voltage / loudness
THE RELATIONSHIP OF VOLTAGE, LOUDNESS, POWER AND DECIBELS | Galen Carol Audio | Galen Carol Audio


i am not a bonafied auditory doctor, but i do have almost 20 years experience as a live sound engineer.

 

[Pops1911]

What a timely thread resurrection. I just bought some new 25 rated ear mupps and some 33 rated ear plugs. I figure I couldn't hear a dynamite explosion in a nitroglycerin factory now! Whoo hoo! Break out those 50cal Desert Iggles maw!

 

[Belial]

Armalite used to send ear plugs in a holder, two Tylenol, and directions to double up with their AR-50's. Doubling up ear protection makes a huge difference when bigger controlled explosions send lead down range for this guy...

 

[P7M13]

Great thread, @Vorpalis - thanks for posting, though I didn't hear a word you said.

 

[11Charlie]

Great thread, @Vorpalis - thanks for posting, though I didn't hear a word you said.

Good thing this site is visual and not audio we all would be hosed!

 

[P7M13]

Good thing this site is visual and not audio we all would be hosed!

Reading and writing with the constant high frequency whistle of tinnitus. If only the notes varied.

 

[Vorpalis]

...if you said a 3db change is either twice or half of the required power output to a speaker (it takes from say an amplifier) ... basicily the a 3db change is only just just barley noticeable

Thanks for the info! This is so cool getting to learn from others' experience!

I would think the wattage sent to a speaker would correlate linearly with the energy of a sound wave – is that true? How does our ears' perception of loudness correlate to the actual energy of a sound wave?

 

[Mygrainman]

I find it interesting the way sound waves travel... lower frequencies go slower and farther, and high frequencies faster but shorter... the lows taking a little distance to fully develop etc... I'm a musician, and had a heck of a bass guitar rig... It had 800 watts 4 10" and 2 15" speakers, and I had to crank it to be heard in the same room as a 100watt guitar amp. BUT... the neighbor 1/4 mile away through the woods could hear only my bass amp, as it rattled the windows in his house.
And with my muzzle brake, if you are directly behind the rifle, it's not bad at all, but for the guy next to me at the range it's LOUD! and it sends of a concussive effect you can feel in your soul.

I double up at the range, not so much for the added protection, but because it helps shut me out and concentrate on my shot... Especially if the guy next to me also has a muzzle brake. I'm still lucky to get sub hour of angle though...

Hearing loss runs in my family, and knock on wood, at 40 I still have excellent hearing... Its a miracle that I do considering all I put my poor ears trough... Two years behind a cannon of a snare drum in HS drum line, and 25 years off and on, playing bass or drums in different bands, and going to rock concerts. and of course 19 years of marriage. only recently have I started using ear pro, but I can still hear her through both layers

 

[SnapShot]

i would say yes higher wattage applied to say a speaker- will make that speaker produce a sound wave that has more energy.... now specifically - what kind of energy do you want to measure. they go about it in slightly different ways.

now how our ears measure it, - easy answer-- differences in pressures

harder answer: that about taps me out.

Amplitude is measured in the amount of force applied over an area. which is measured in Newtons per square meter (N/m2). (if you think of what a wave from looks like - the amplitude is the measurement between the very top of the wave and the very bottom)

WATT - the easiest way i can describe a Watt is that its a measurement of energy over time . 1 watt = 1 Newton of work per second


then there is the dB Decibel which is a measurement of intensity, "the power of the original sound source along with distance of measurement from the sound source combine to form the intensity"


heres where stuff gets converted around like a math formula. if you want the equation ill give you a link, but that stuff is beyond my caring.

now while a doubling of power way wattage is +3dB, but the doubling of AMPlitude is +6dB

science of what happens in the ear,, some of it is pretty complicated, but if your into that stuff.

<broken link removed>


pretty good explanation - where i sourced some info from

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