Actual Noise Reduction of a 5.56 suppressor????

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Posted: 11/26/2008 8:39:37 AM EDT

I have been reading through these threads and have continually seen that a noise suppressor on a 5.56 will reduce noise approxiamately 30db??

But I have been looking at AAC and all their suppressors state that they remove appoximately 95% of the sound........

What am I missing if an average high powered rifle is around 140-160db's...then 95% of that would be a reduction of between 133db-142db??

Someone show me the light––LOL!!!

Posted: 11/26/2008 8:49:17 AM EDT

[#1]

Basically, 5.56 suppressors reduce the noise to a level at which some may be comfortable without ear pro, and some may not.

I am fine shooting a suppressed 5.56 gun without ear protection.

Posted: 11/26/2008 8:55:59 AM EDT

[#2]

Can you provide a source to where AAC says that their suppressors reduce 95% of the sound? While some of them may be prone to running off at the mouth, I don't think they'd say something that dumb.

Posted: 11/26/2008 9:12:24 AM EDT

[#3]

Sound (decibels) is not linear. A suppressed 5.56/223 sounds like a 22lr rifle (without a silencer). It is actually a hair quieter in decibels, but you get the supersonic crack.

Posted: 11/26/2008 10:02:58 AM EDT

[#4]

Quoted:
Can you provide a source to where AAC says that their suppressors reduce 95% of the sound? While some of them may be prone to running off at the mouth, I don't think they'd say something that dumb.

I've seen this several times.

97% of muzzle report

The good cans will make the gun quiet enough to shoot without ear protection. Some AAC silencers on some barrel lengths will do that. Sometimes this depends on gas ports and springs and buffers to some extent too.

As far as a percentage of sound- that would be tough for me to quantify. If I had to guess I would say guns get 70-80% quieter, but that's a guess. 97% would seem like a figure I would put at normal conversation levels like 80-85 DB's, and these levels are WAY below bullet flight noise, and theoretically I'm not even sure they are possible, let alone in a sale-able (IE compact) rifle mountable silencer.

Posted: 11/26/2008 11:34:56 AM EDT

[#5]

Why would you guess? Do you not understand the logarithmic scale on which decibels are measured?

Decibels are counted on a base-10 logarithmic scale. 1dB is measured as a sound intensity of 10^-12 Watts per square meter (or 20 micropascals of sound pressure). From there, everything is calculated as 10 raised to the power of the number of bels (1 bel = 10 decibels) of sound intensity.

If the intensity of 1dB = 10^-12 W/m^2 = "I", then

10dB = 10^1 = 10 x I
20dB = 10^2 = 100 x I
30dB = 10^3 = 1000 x I
40dB = 10^4 = 10000 x I

Etcetera. Thus,

160dB = 10^16 = 10000000000000000 x I, or 10 quadrillion times more intense than a sound of 1dB.

130dB = 10^13 x I, or 99.9% less intense than a 160dB sound. It is perfectly reasonable and correct to say that a 30dB can removes over 95% of sound intensity.

Another way to do this math is that each additional decibel represents a 26% increase in sound intensity. Thus, a 160dB sound is 1.26^30 = 1026 times more intense than a 130dB sound.

Posted: 11/26/2008 1:31:40 PM EDT

[#6]

Quoted:
Why would you guess? Do you not understand the logarithmic scale on which decibels are measured?

Decibels are counted on a base-10 logarithmic scale. 1dB is measured as a sound intensity of 10^-12 Watts per square meter (or 20 micropascals of sound pressure). From there, everything is calculated as 10 raised to the power of the number of bels (1 bel = 10 decibels) of sound intensity.

If the intensity of 1dB = 10^-12 W/m^2 = "I", then

10dB = 10^1 = 10 x I
20dB = 10^2 = 100 x I
30dB = 10^3 = 1000 x I
40dB = 10^4 = 10000 x I

Etcetera. Thus,

160dB = 10^16 = 10000000000000000 x I, or 10 quadrillion times more intense than a sound of 1dB.

130dB = 10^13 x I, or 99.9% less intense than a 160dB sound. It is perfectly reasonable and correct to say that a 30dB can removes over 95% of sound intensity.

Another way to do this math is that each additional decibel represents a 26% increase in sound intensity. Thus, a 160dB sound is 1.26^30 = 1026 times more intense than a 130dB sound.

Most people don't perceive sounds in the logarithmic scale format. The way sound naturally dampens itself in air, it's not going to be something anyone but a scientist perceives as 97% reduction in sound.

So the logarithmic argument while accurate is probably not going to reflect what people perceive when they hear the device.

In other words stand in an open field, fire an M4, then step 25 meters to the rear and have someone at the original location fire it again, now pick up a suppressed M4, fire it, and the sound intensity will probably feel similar to the unsuppressed at 25 meters. 97%? It likely won't leave the human ear convinced he's actually heard a sound 3% that of the original.

97% is highly likely to give people an unrealistic expectation of what they are going to hear.

This argument is a lot like massive gain numbers in night vision tubes. Do we percieve 50,000 times more light? No. Do we now see something where there was a shadow? yes.

Posted: 11/26/2008 1:42:37 PM EDT

[#7]

Quoted:

In other words stand in an open field, fire an M4, then step 25 meters to the rear and have someone at the original location fire it again, now pick up a suppressed M4, fire it, and the sound intensity will probably feel similar to the unsuppressed at 25 meters.

I think the suppressed gun at the shooter would sound a lot quieter than the unsuppressed gun at 25M.

But yes, describing sound reduction as a percentage is going to confuse those who don't understand the details. For that matter, the same is true when giving dB figures.

Posted: 11/26/2008 1:55:52 PM EDT

[#8]

AAC does say 97 percent of the muzzle report. But I believe some of that 97 percent of the report is for the flash as well.

"Civilian sport shooters marvel at the reduction in group size and the ability to witness bullet impact through their optic due to a reduction in recoil of up to 60 percent and a 97 percent reduction in muzzle report." that is quoted directly from AAC's website.

My thoughts is that with shooting supressed it not only reduces the noise but also the flash that may hinder some shooters. Hence the 97 percent reduction in muzzle report.

Posted: 11/26/2008 2:07:19 PM EDT

[#9]

Most people don't perceive sounds in the logarithmic scale format.

Then why even measure in decibels? As long as you are comfortable saying "The bushwhacker is a 32dB can" you should be comfortable with other companies expressing their NSR in a logarithmic fashion. There's really no difference in saying "30dB reduction" vs "97% reduction in sound pressure level." Just different scientific ways of saying the exact same thing.

Posted: 11/26/2008 3:27:06 PM EDT

[#10]

Quoted:

Most people don't perceive sounds in the logarithmic scale format.

Then why even measure in decibels? As long as you are comfortable saying "The bushwhacker is a 32dB can" you should be comfortable with other companies expressing their NSR in a logarithmic fashion. There's really no difference in saying "30dB reduction" vs "97% reduction in sound pressure level." Just different scientific ways of saying the exact same thing.

The problem is that 97% or 99.9% or whatever is quite misleading. Take anyone who has never shot a 556 suppressed and let them fire one suppressed shot and ask them to guess a percentage of an unsuppressed shot. Not ONE will say 97%. Most will probably say 50% or less.

Posted: 11/26/2008 4:12:54 PM EDT

[#11]

Quoted:
Why would you guess? Do you not understand the logarithmic scale on which decibels are measured?

Decibels are counted on a base-10 logarithmic scale. 1dB is measured as a sound intensity of 10^-12 Watts per square meter (or 20 micropascals of sound pressure). From there, everything is calculated as 10 raised to the power of the number of bels (1 bel = 10 decibels) of sound intensity.

If the intensity of 1dB = 10^-12 W/m^2 = "I", then

10dB = 10^1 = 10 x I
20dB = 10^2 = 100 x I
30dB = 10^3 = 1000 x I
40dB = 10^4 = 10000 x I

Etcetera. Thus,

160dB = 10^16 = 10000000000000000 x I, or 10 quadrillion times more intense than a sound of 1dB.

130dB = 10^13 x I, or 99.9% less intense than a 160dB sound. It is perfectly reasonable and correct to say that a 30dB can removes over 95% of sound intensity.

Another way to do this math is that each additional decibel represents a 26% increase in sound intensity. Thus, a 160dB sound is 1.26^30 = 1026 times more intense than a 130dB sound.

While accurate this does not fully characterize the situation. Its extremely important to know in what frequencies the sound is carrying its energy, and weather or not a suppressor will dampen the energy in each frequency by an equal amount. I would guess that it does not. This is important because a sound with X energy at A Hz will NOT necessarily be perceived the same as another sound of X energy at B Hz. I have never seen an energy plot of a gunshot with and without a suppressor in the frequency domain, nor do I know the "transfer function"

of a human ear.

OP...sorry I cant say much about AACs claim. I always just assume that any number any suppressor manufacture publishes is bullshit. Buy based on what sounds good to you, and on price.

Posted: 11/26/2008 4:48:09 PM EDT

[#12]

Quoted:

Most people don't perceive sounds in the logarithmic scale format.

Then why even measure in decibels? As long as you are comfortable saying "The bushwhacker is a 32dB can" you should be comfortable with other companies expressing their NSR in a logarithmic fashion. There's really no difference in saying "30dB reduction" vs "97% reduction in sound pressure level." Just different scientific ways of saying the exact same thing.

The problem is that 97% or 99.9% or whatever is quite misleading. Take anyone who has never shot a 556 suppressed and let them fire one suppressed shot and ask them to guess a percentage of an unsuppressed shot. Not ONE will say 97%. Most will probably say 50% or less.

That's really what I'm trying to say. I think the DB reduction figure is a lot easier for someone to grasp when they see a unsuppressed SPL of 165, and then see a suppressed one of 134, they can think of it as getting rid of some sound, as opposed to trying to imagine what 97% of sound removed is going to be like.

Then they can compare the 134 SPL to the 122 of a decent .22lr pistol can, and realize it's going to be noisy, but not ear shattering. That way when they fire the first shot they can say, "Cool." Instead of "WTF?"

Posted: 11/26/2008 7:51:08 PM EDT

[#13]

Quoted:

Most people don't perceive sounds in the logarithmic scale format.

Then why even measure in decibels? As long as you are comfortable saying "The bushwhacker is a 32dB can" you should be comfortable with other companies expressing their NSR in a logarithmic fashion. There's really no difference in saying "30dB reduction" vs "97% reduction in sound pressure level." Just different scientific ways of saying the exact same thing.

The problem is that 97% or 99.9% or whatever is quite misleading. Take anyone who has never shot a 556 suppressed and let them fire one suppressed shot and ask them to guess a percentage of an unsuppressed shot. Not ONE will say 97%. Most will probably say 50% or less.

That's really what I'm trying to say. I think the DB reduction figure is a lot easier for someone to grasp when they see a unsuppressed SPL of 165, and then see a suppressed one of 134, they can think of it as getting rid of some sound, as opposed to trying to imagine what 97% of sound removed is going to be like.

Then they can compare the 134 SPL to the 122 of a decent .22lr pistol can, and realize it's going to be noisy, but not ear shattering. That way when they fire the first shot they can say, "Cool." Instead of "WTF?"

Its easier to understand with DB reduction than a %. Comparing it in terms of .22lr rifles & pistols (unsuppressed) is usually the best way to get it across. I think this is because 22lr (rifle) is the most often shot gun w/o hearing protection

Posted: 11/26/2008 10:01:27 PM EDT

[#14]

Quoted:
Why would you guess? Do you not understand the logarithmic scale on which decibels are measured?

Decibels are counted on a base-10 logarithmic scale. 1dB is measured as a sound intensity of 10^-12 Watts per square meter (or 20 micropascals of sound pressure). From there, everything is calculated as 10 raised to the power of the number of bels (1 bel = 10 decibels) of sound intensity.

If the intensity of 1dB = 10^-12 W/m^2 = "I", then

10dB = 10^1 = 10 x I
20dB = 10^2 = 100 x I
30dB = 10^3 = 1000 x I
40dB = 10^4 = 10000 x I

Etcetera. Thus,

160dB = 10^16 = 10000000000000000 x I, or 10 quadrillion times more intense than a sound of 1dB.

130dB = 10^13 x I, or 99.9% less intense than a 160dB sound. It is perfectly reasonable and correct to say that a 30dB can removes over 95% of sound intensity.

Another way to do this math is that each additional decibel represents a 26% increase in sound intensity. Thus, a 160dB sound is 1.26^30 = 1026 times more intense than a 130dB sound.

Posted: 11/26/2008 10:09:06 PM EDT

[#15]

Quoted:

Most people don't perceive sounds in the logarithmic scale format.

Then why even measure in decibels? As long as you are comfortable saying "The bushwhacker is a 32dB can" you should be comfortable with other companies expressing their NSR in a logarithmic fashion. There's really no difference in saying "30dB reduction" vs "97% reduction in sound pressure level." Just different scientific ways of saying the exact same thing.

You are such a troll...

Foolishly supporting AAC's CRAP with your own idiotic comments AND belittling Green0's statements with BS is just asinine. Give it up, would you please?

AAC LOVES to use misleading figures, even if somehow they are tied to reality. Opening your mouth about things such as this is just proving to some people what a lot of us already know...

Posted: 11/27/2008 3:24:44 AM EDT

[#16]

08ravenR1,

When I shot my Gemtech G5 from my 16" Bushie the first time, I was standing next to a guy with a lever .22LR that had a shot barrel (don't know the brand––it was an 1950s-made .22LR)––they range guys all said the .22LR was a little louder than the AR.

If you're expecting 'Hollywood quiet" you'll be very disappointed. As has been already said––most folks shooting say that it sounds like 50% of the noise is gone––not 97%.

I think you have to consider––what are you looking for? If you need REEEAAAL quiet, a .22LR may be what you want. OTOH, my AAC Evo9 Glock17 is quiet enough to shoot without ear protection––maybe a 9mm carbine would be more of what you're looking for? Not sure.

Posted: 11/27/2008 5:04:28 AM EDT

[#17]

Quoted:Foolishly supporting AAC's CRAP with your own idiotic comments AND belittling Green0's statements with BS is just asinine.

Would you care to point out what part of my post was BS? Every bit of it is true and easily verifiable to anyone who understands math above a 10th grade level.

Anyone who actually understands what decibels are will hear "30dB reduction" and immediately know that it's a 10^3 or 99.9% reduction in intensity. What you are basically saying is "most of us are too stupid to conceptualize this, so we prefer our information in a form that caters to us."

Posted: 11/27/2008 5:10:40 AM EDT

[#18]

Quoted:

Most people don't perceive sounds in the logarithmic scale format.

Then why even measure in decibels? As long as you are comfortable saying "The bushwhacker is a 32dB can" you should be comfortable with other companies expressing their NSR in a logarithmic fashion. There's really no difference in saying "30dB reduction" vs "97% reduction in sound pressure level." Just different scientific ways of saying the exact same thing.

The problem is that 97% or 99.9% or whatever is quite misleading. Take anyone who has never shot a 556 suppressed and let them fire one suppressed shot and ask them to guess a percentage of an unsuppressed shot. Not ONE will say 97%. Most will probably say 50% or less.

I concur,

My opinion is that for your average shooter or hunter, it is not the best way to convey the effectiveness of the suppressor.

Mentioning the sound pressure level of the weapon without a suppressor, hearing damage / pain threshold and what the suppressed SPL will be, will give a better sense of the effectiveness.

Posted: 11/27/2008 5:11:58 AM EDT

[#19]

Quoted:I think the DB reduction figure is a lot easier for someone to grasp when they see a unsuppressed SPL of 165, and then see a suppressed one of 134, they can think of it as getting rid of some sound, as opposed to trying to imagine what 97% of sound removed is going to be like.

Again, you're saying "most people are clueless about what decibels are, so let's cater to them."

I agree that 95% of the American public are dipshits and have no clue what a logarithm is or how decibels work. That doesn't mean I get pissy at AAC for saying something that is perfectly accurate, and verifiable by anyone with a calculator. 90% of people don't know what a "BTU" is, but they still want a furnace with lots of them.

Posted: 11/27/2008 5:19:20 AM EDT

[#20]

I had a HALO on a 16" barrel. It was like shooting a .22lr or .22mag, sound wise. I could not shoot without hearing protection. I was shooting at an outdoor range with concrete over hangs, so the sound was there. With Subsonic ammo it was better.

Posted: 11/27/2008 6:48:37 AM EDT

[#21]

Be thankfull and knock the crap off.

Posted: 11/27/2008 8:53:20 AM EDT

[#22]

Sorry Matt I didn't mean to get crappy but some of those statements are just insulting- I don't know who learned decibel logarithms in 10th grade...

I'm surprised you still needed hearing protection with the Halo- it was definitely the concrete around you- more than likely, you'd have that problem with any supersonic ammo through a suppressor. When I shoot outside, you hear the pfffft of the gun and THEN you get the crack a split second later when it echoes off of the ground and berms...

Posted: 11/27/2008 8:59:56 AM EDT

[#23]

Quoted:

I don't know who learned decibel logarithms in 10th grade...

Lots of people did.

You could make the same statements without resorting to name calling and insulting tactics. You're just so damn angry.

Posted: 11/27/2008 10:06:28 AM EDT

[#24]

Hmmm... I never heard the 97% reduction figure untill just now and I knew that it was based off a logarithmic difference as soon as I read it. Anyone with enough knowledge to even consider db figures probably knows this. I dont see how this is misleading at all. Just saying a suppressor reduces SPL a specific db figure is JUST as misleading. It depends on ammo, barrel length, weapon used, etc. Saying a silencer reduces SPL 40db some odd, unstandardised figure downrange is more misleading.

If a marketing person can say something is 100% stronger or the other product is only 50% as strong, the larger figure is what they will pick.

AAC's figure is correct. I guess they stated the factual figures. I dont see whats so horrible about that.

Posted: 11/27/2008 10:07:53 AM EDT

[#25]

Quoted:
I have been reading through these threads and have continually seen that a noise suppressor on a 5.56 will reduce noise approxiamately 30db??

But I have been looking at AAC and all their suppressors state that they remove appoximately 95% of the sound........

What am I missing if an average high powered rifle is around 140-160db's...then 95% of that would be a reduction of between 133db-142db??

Someone show me the light––LOL!!!

Yeah, you have it right. You have already seen the light. Your figures are about what 5.56 silencers do. I guess I dont understand why this turned into a pissing match thread.

Posted: 11/27/2008 10:35:39 AM EDT

[#26]

Quoted:

Quoted:

I have been reading through these threads and have continually seen that a noise suppressor on a 5.56 will reduce noise approxiamately 30db??
But I have been looking at AAC and all their suppressors state that they remove appoximately 95% of the sound........
What am I missing if an average high powered rifle is around 140-160db's...then 95% of that would be a reduction of between 133db-142db??
Someone show me the light––LOL!!!

Yeah, you have it right. You have already seen the light. Your figures are about what 5.56 silencers do. I guess I dont understand why this turned into a pissing match thread.

No kidding - it's a shame that so many threads here do.

Posted: 11/27/2008 10:49:27 AM EDT

[#27]

The uneducated red neck perspective:

I am not going to get into all the math, but I wouldn't be surprised if any decent 5.56 suppressor reduces the MUZZLE REPORT by 97%. That statement doesn't say that if you fire the gun with then without the suppressor that you say the sound was reduced by 97% (even if this is true mathmatically).
The muzzle report is one thing. The muzzle report plus the sound of the sonic crack is another thing. The sonic crack is NOT part of the muzzle report.
If you fire a subsonic round that only gives muzzle report with no sonic crack, then it probably would seem to reduce the report by some huge percentage over an unsupressed rifle shot.

Point being: when you fire a suppressed 5.56 rifle with normal supersonic ammo, it sounds about like firing a .22 rifle without a suppressor (at least it does to me).

Firing a .22 rifle with a suppressor and normal supersonic ammo sounds to me like the suppressor isn't doing anything.
This leads me to believe that when firing a .22 rifle, the vast majority of what you are hearing is the sonic crack of the supersonic bullet and NOT the muzzle report.

Firing a 5.56 rifle with subsonic ammo is similar, if not quieter than firing a suppressed .22 rifle firing subsonic ammo. This would be only muzzle report without the supersonic crack.

I realize that the muzzle report of a load using more powder (supersonic round) vs. a load using less powder (the subsonic round) is going to be louder. But I am just making a very general point.

Posted: 11/27/2008 12:54:28 PM EDT

[#28]

Quoted:
You are such a troll...

Foolishly supporting AAC's CRAP with your own idiotic comments AND belittling Green0's statements with BS is just asinine. Give it up, would you please?

AAC LOVES to use misleading figures, even if somehow they are tied to reality. Opening your mouth about things such as this is just proving to some people what a lot of us already know...

Wait...what?

You're calling him a troll for supporting AAC's "Crap" that's actually truthful, accurate information?

I don't see how they're misleading either. Just because someone "perceives" differently from what the statistics say doesn't make the statistics inaccurate.

Posted: 11/27/2008 1:46:38 PM EDT

[#29]

Quoted:
I don't know who learned decibel logarithms in 10th grade...

I learned about logarithms in 7th grade Earth Science class, when we learned about the Richter scale. I assumed 10th grade would be a healthy margin for most people. I cannot imagine being a junior in high school and never having heard of exponents.

Posted: 11/27/2008 1:53:27 PM EDT

[#30]

Something went wrong ,i try again

Posted: 11/27/2008 1:59:14 PM EDT

[#31]

Quoted:

Quoted:
Why would you guess? Do you not understand the logarithmic scale on which decibels are measured?

Decibels are counted on a base-10 logarithmic scale. 1dB is measured as a sound intensity of 10^-12 Watts per square meter (or 20 micropascals of sound pressure). From there, everything is calculated as 10 raised to the power of the number of bels (1 bel = 10 decibels) of sound intensity.

If the intensity of 1dB = 10^-12 W/m^2 = "I", then

10dB = 10^1 = 10 x I
20dB = 10^2 = 100 x I
30dB = 10^3 = 1000 x I
40dB = 10^4 = 10000 x I

Etcetera. Thus,

160dB = 10^16 = 10000000000000000 x I, or 10 quadrillion times more intense than a sound of 1dB.

130dB = 10^13 x I, or 99.9% less intense than a 160dB sound. It is perfectly reasonable and correct to say that a 30dB can removes over 95% of sound intensity.

Another way to do this math is that each additional decibel represents a 26% increase in sound intensity. Thus, a 160dB sound is 1.26^30 = 1026 times more intense than a 130dB sound.

Most people don't perceive sounds in the logarithmic scale format. The way sound naturally dampens itself in air, it's not going to be something anyone but a scientist perceives as 97% reduction in sound.

So the logarithmic argument while accurate is probably not going to reflect what people perceive when they hear the device.

In other words stand in an open field, fire an M4, then step 25 meters to the rear and have someone at the original location fire it again, now pick up a suppressed M4, fire it, and the sound intensity will probably feel similar to the unsuppressed at 25 meters. 97%? It likely won't leave the human ear convinced he's actually heard a sound 3% that of the original.

97% is highly likely to give people an unrealistic expectation of what they are going to hear.

This argument is a lot like massive gain numbers in night vision tubes. Do we percieve 50,000 times more light? No. Do we now see something where there was a shadow? yes.

What do you mean by that ??? thats makes no sens

sound DOES NOT naturally dampens itself in air like you describe

Could you please explain ?

Posted: 11/27/2008 5:42:46 PM EDT

[#32]

Quoted:

Quoted:
I don't know who learned decibel logarithms in 10th grade...

I learned about logarithms in 7th grade Earth Science class, when we learned about the Richter scale. I assumed 10th grade would be a healthy margin for most people. I cannot imagine being a junior in high school and never having heard of exponents.

As a college graduate, I've been over logarithms way more than I would have ever wanted to. I still don't "hear" in logarithms. I don't think that most people can truly understand the difference a suppressor makes without actually hearing good quality sound or being there and trying it. Perception of sound (which is what people consider hearing) is different for every person and can be different on any given day.

Posted: 11/27/2008 6:50:29 PM EDT

[#33]

Quoted:

Most people don't perceive sounds in the logarithmic scale format.

Then why even measure in decibels? As long as you are comfortable saying "The bushwhacker is a 32dB can" you should be comfortable with other companies expressing their NSR in a logarithmic fashion. There's really no difference in saying "30dB reduction" vs "97% reduction in sound pressure level." Just different scientific ways of saying the exact same thing.

You are such a troll...

Foolishly supporting AAC's CRAP with your own idiotic comments AND belittling Green0's statements with BS is just asinine. Give it up, would you please?

AAC LOVES to use misleading figures, even if somehow they are tied to reality. Opening your mouth about things such as this is just proving to some people what a lot of us already know...

MAND why are the majority of your posts in the silencer section turn out to be a pissing match over aac? have you not read the CoC for this forum?

Posted: 11/27/2008 7:14:42 PM EDT

[#34]

Quoted:

MAND why are the majority of your posts in the silencer section turn out to be a pissing match over aac? have you not read the CoC for this forum?

Yeah, IP check, please.

Posted: 11/27/2008 7:37:45 PM EDT

[#35]

MY posts turn into a pissing match? It seems there are a few that take offense to what I say- they all have one thing in common too. And I'm not the only one certain people like to go after. I'm also not the only one who has a problem with certain things said here.

Go ahead and check my IP.

Posted: 11/27/2008 7:37:57 PM EDT

[#36]

Quoted:

Quoted:
Why would you guess? Do you not understand the logarithmic scale on which decibels are measured?

Decibels are counted on a base-10 logarithmic scale. 1dB is measured as a sound intensity of 10^-12 Watts per square meter (or 20 micropascals of sound pressure). From there, everything is calculated as 10 raised to the power of the number of bels (1 bel = 10 decibels) of sound intensity.

If the intensity of 1dB = 10^-12 W/m^2 = "I", then

10dB = 10^1 = 10 x I
20dB = 10^2 = 100 x I
30dB = 10^3 = 1000 x I
40dB = 10^4 = 10000 x I

Etcetera. Thus,

160dB = 10^16 = 10000000000000000 x I, or 10 quadrillion times more intense than a sound of 1dB.

130dB = 10^13 x I, or 99.9% less intense than a 160dB sound. It is perfectly reasonable and correct to say that a 30dB can removes over 95% of sound intensity.

Another way to do this math is that each additional decibel represents a 26% increase in sound intensity. Thus, a 160dB sound is 1.26^30 = 1026 times more intense than a 130dB sound.

Most people don't perceive sounds in the logarithmic scale format. The way sound naturally dampens itself in air, it's not going to be something anyone but a scientist perceives as 97% reduction in sound.

So the logarithmic argument while accurate is probably not going to reflect what people perceive when they hear the device.

In other words stand in an open field, fire an M4, then step 25 meters to the rear and have someone at the original location fire it again, now pick up a suppressed M4, fire it, and the sound intensity will probably feel similar to the unsuppressed at 25 meters. 97%? It likely won't leave the human ear convinced he's actually heard a sound 3% that of the original.

97% is highly likely to give people an unrealistic expectation of what they are going to hear.

This argument is a lot like massive gain numbers in night vision tubes. Do we percieve 50,000 times more light? No. Do we now see something where there was a shadow? yes.

What do you mean by that ??? thats makes no sens

sound DOES NOT naturally dampens itself in air like you describe

Could you please explain ?

Sound is pressure- so I think every meter distant from the source should yield about a 1DB drop. I remember reading that in something Mark White had written. It may or may not be accurate but sounds possible, given a couple meters from an M4 often drops noise to something that stops ringing ears.

When you pull the trigger and hear something on the order of what the unsuppressed firearm sounds like at 25-30 meters, it really doesn't leave too many people with the impression 97% of sound is gone.

The bullet flight is about 133DBs and that's nearly the level of some of the best silencers on the market so the argument that the bullet flight noise is the offending party isn't really completely accurate. The suppressed report is still loud.

Posted: 11/28/2008 3:50:17 AM EDT

[#37]

Quoted:

Quoted:
Why would you guess? Do you not understand the logarithmic scale on which decibels are measured?

Decibels are counted on a base-10 logarithmic scale. 1dB is measured as a sound intensity of 10^-12 Watts per square meter (or 20 micropascals of sound pressure). From there, everything is calculated as 10 raised to the power of the number of bels (1 bel = 10 decibels) of sound intensity.

If the intensity of 1dB = 10^-12 W/m^2 = "I", then

10dB = 10^1 = 10 x I
20dB = 10^2 = 100 x I
30dB = 10^3 = 1000 x I
40dB = 10^4 = 10000 x I

Etcetera. Thus,

160dB = 10^16 = 10000000000000000 x I, or 10 quadrillion times more intense than a sound of 1dB.

130dB = 10^13 x I, or 99.9% less intense than a 160dB sound. It is perfectly reasonable and correct to say that a 30dB can removes over 95% of sound intensity.

Another way to do this math is that each additional decibel represents a 26% increase in sound intensity. Thus, a 160dB sound is 1.26^30 = 1026 times more intense than a 130dB sound.

Most people don't perceive sounds in the logarithmic scale format. The way sound naturally dampens itself in air, it's not going to be something anyone but a scientist perceives as 97% reduction in sound.

So the logarithmic argument while accurate is probably not going to reflect what people perceive when they hear the device.

In other words stand in an open field, fire an M4, then step 25 meters to the rear and have someone at the original location fire it again, now pick up a suppressed M4, fire it, and the sound intensity will probably feel similar to the unsuppressed at 25 meters. 97%? It likely won't leave the human ear convinced he's actually heard a sound 3% that of the original.

97% is highly likely to give people an unrealistic expectation of what they are going to hear.

This argument is a lot like massive gain numbers in night vision tubes. Do we percieve 50,000 times more light? No. Do we now see something where there was a shadow? yes.

What do you mean by that ??? thats makes no sens

sound DOES NOT naturally dampens itself in air like you describe

Could you please explain ?

Sound is pressure- so I think every meter distant from the source should yield about a 1DB drop. I remember reading that in something Mark White had written. It may or may not be accurate but sounds possible, given a couple meters from an M4 often drops noise to something that stops ringing ears.

When you pull the trigger and hear something on the order of what the unsuppressed firearm sounds like at 25-30 meters, it really doesn't leave too many people with the impression 97% of sound is gone.

The bullet flight is about 133DBs and that's nearly the level of some of the best silencers on the market so the argument that the bullet flight noise is the offending party isn't really completely accurate. The suppressed report is still loud.

Sure ,but you wrote it like the air itself was dampening the sound ,its not (ok a tiny bit )

But just because it really doesn't leave too many people with the impression of a 97% reduction ,,it still is

And your example is missing ,that the tone of a unsupressed 5,56 is much deeper ,so people think of the deep sound as loud and the suppressed high pitch as something els

But here is it that the db is coming in again humans are lousy to judge sound to say it nice

Thats why the db scale was invented ,,so thats why it is used ,just because people dont "feel " like it can be true ,it still is

Its the same with light ,we humans can not say when the light intensity is half of something we just did see ,so again we use a logarithmic scale

To all those nay sayers about DB ,go tell the military that they use a wrong testing method ,the method that is accepted by most of the industry

Posted: 11/28/2008 6:57:19 AM EDT

[#38]

Quoted:

MY posts turn into a pissing match? It seems there are a few that take offense to what I say

No, they take offense to how you go about saying it. You turn a civil discussion into a name-calling argument. Very few people here care that you hate AAC. You're not a martyr who's "fighting the good fight." You're a brat.

Posted: 11/28/2008 7:39:40 AM EDT

[#39]

Quoted:
But just because it really doesn't leave too many people with the impression of a 97% reduction ,,it still is

And your example is missing ,that the tone of a unsupressed 5,56 is much deeper ,so people think of the deep sound as loud and the suppressed high pitch as something els

But here is it that the db is coming in again humans are lousy to judge sound to say it nice

Thats why the db scale was invented ,,so thats why it is used ,just because people dont "feel " like it can be true ,it still is

Its the same with light ,we humans can not say when the light intensity is half of something we just did see ,so again we use a logarithmic scale

To all those nay sayers about DB ,go tell the military that they use a wrong testing method ,the method that is accepted by most of the industry

Well said.

Posted: 11/28/2008 8:32:52 AM EDT

[#40]

Quoted:

Sure ,but you wrote it like the air itself was dampening the sound ,its not (ok a tiny bit )

But just because it really doesn't leave too many people with the impression of a 97% reduction ,,it still is

And your example is missing ,that the tone of a unsupressed 5,56 is much deeper ,so people think of the deep sound as loud and the suppressed high pitch as something els

But here is it that the db is coming in again humans are lousy to judge sound to say it nice

Thats why the db scale was invented ,,so thats why it is used ,just because people dont "feel " like it can be true ,it still is

Its the same with light ,we humans can not say when the light intensity is half of something we just did see ,so again we use a logarithmic scale

To all those nay sayers about DB ,go tell the military that they use a wrong testing method ,the method that is accepted by most of the industry

DB isn't the issue, I just can only think of 3-4 people I know who actually understand that 160db to 130db is a 97% reduction, and that's some audiophiles and sound engineers. Using the 97% reduction in sound (report, whatever) is fine, but there should also be another down to earth comparison for others as well. I'd rather have way too much information about a product than not nearly enough.

Posted: 11/28/2008 8:45:43 AM EDT

[#41]

Quoted:

DB isn't the issue, I just can only think of 3-4 people I know who actually understand that 160db to 130db is a 97% reduction, and that's some audiophiles and sound engineers. Using the 97% reduction in sound (report, whatever) is fine, but there should also be another down to earth comparison for others as well. I'd rather have way too much information about a product than not nearly enough.

Using dB is misleading as well. People either are informed consumers or just like to think they are.

Clearly using the 97% number is marketing, but then so is publishing dB numbers. The companies that don't publish any sound reduction numbers are onto something –– it reduces the number of internet asshats who badmouth your company. I don't trust the claims any silencer companies. It's a crooked industry, IMO.

Posted: 11/28/2008 9:02:05 AM EDT

[#42]

Quoted:

Using dB is misleading as well. People either are informed consumers or just like to think they are.

Clearly using the 97% number is marketing, but then so is publishing dB numbers. The companies that don't publish any sound reduction numbers are onto something –– it reduces the number of internet asshats who badmouth your company. I don't trust the claims any silencer companies. It's a crooked industry, IMO.

I honestly think 2-4 db difference in cans makes little difference as a feature. QD, weight, etc. are more important than the differences in sound reduction in any given rifle.

Posted: 11/28/2008 2:28:19 PM EDT

[#43]

Quoted:

Quoted:

Using dB is misleading as well. People either are informed consumers or just like to think they are.

Clearly using the 97% number is marketing, but then so is publishing dB numbers. The companies that don't publish any sound reduction numbers are onto something –– it reduces the number of internet asshats who badmouth your company. I don't trust the claims any silencer companies. It's a crooked industry, IMO.

I honestly think 2-4 db difference in cans makes little difference as a feature. QD, weight, etc. are more important than the differences in sound reduction in any given rifle.

Thats actually the point of it all
A reduction of 3 db is cutting the energy in half

So a can that do that has achieved not a little ,but much

Try to look at it like this

You have a cake

take 3db away
You now have a 1/2 cake
That was much
Now do it again
You now have a 1/4 cake (the half of a half is 1/4)
Do it again
You now have a 1/8 cake
again
1/16

you see, you will never get rid of the cake

But the first part is always the biggest

thats why the upper few DB is so important ,,if you care about the cans ability to suppress sound

DB rules the show

Posted: 11/28/2008 2:40:53 PM EDT

[#44]

Quoted:

Quoted:

Using dB is misleading as well. People either are informed consumers or just like to think they are.

Clearly using the 97% number is marketing, but then so is publishing dB numbers. The companies that don't publish any sound reduction numbers are onto something –– it reduces the number of internet asshats who badmouth your company. I don't trust the claims any silencer companies. It's a crooked industry, IMO.

I honestly think 2-4 db difference in cans makes little difference as a feature. QD, weight, etc. are more important than the differences in sound reduction in any given rifle.

Thats actually the point of it all
A reduction of 3 db is cutting the energy in half

So a can that do that has achieved not a little ,but much

Try to look at it like this

You have a cake

take 3db away
You now have a 1/2 cake
That was much
Now do it again
You now have a 1/4 cake (the half of a half is 1/4)
Do it again
You now have a 1/8 cake
again
1/16

you see, you will never get rid of the cake

But the first part is always the biggest

thats why the upper few DB is so important ,,if you care about the cans ability to suppress sound

DB rules the show

I like your example, as it can give everybody an idea of what you mean. Most folks don't get logarithms, even if I do. Your cake example is a good way to help those who can't or (most likely) don't want to know the nitty gritty of it all.

Posted: 11/28/2008 3:00:02 PM EDT

[#45]

Quoted:

Quoted:

Using dB is misleading as well. People either are informed consumers or just like to think they are.

Clearly using the 97% number is marketing, but then so is publishing dB numbers. The companies that don't publish any sound reduction numbers are onto something –– it reduces the number of internet asshats who badmouth your company. I don't trust the claims any silencer companies. It's a crooked industry, IMO.

I honestly think 2-4 db difference in cans makes little difference as a feature. QD, weight, etc. are more important than the differences in sound reduction in any given rifle.

Thats actually the point of it all
A reduction of 3 db is cutting the energy in half

So a can that do that has achieved not a little ,but much

Try to look at it like this

You have a cake

take 3db away
You now have a 1/2 cake
That was much
Now do it again
You now have a 1/4 cake (the half of a half is 1/4)
Do it again
You now have a 1/8 cake
again
1/16

you see, you will never get rid of the cake

But the first part is always the biggest

thats why the upper few DB is so important ,,if you care about the cans ability to suppress sound

DB rules the show

It is a good place to start but it still comes down to the individual's hearing. Unfortunately most people don't get the oppurtunity to hear/shoot different suppressors before buying one.
So once again it comes down to features, reported db reduction and price.

Posted: 11/28/2008 4:32:58 PM EDT

[#46]

Quoted:Sound is pressure- so I think every meter distant from the source should yield about a 1DB drop. I remember reading that in something Mark White had written.

What a surprise - something you heard from someone else and repeated on a forum is incorrect.

Sound intensity and pressure decrease on a curve inversely proportional to distance from the source. Doubling the distance will halve the sound intensity (ie, reduce it by 6dB) - whether the doubling is from 1m to 2m or 10m to 20m.

Posted: 11/28/2008 4:56:48 PM EDT

[#47]

Quoted:

I think every meter distant from the source should yield about a 1DB drop.

So a typical 5.56 unsuppressed firearm is 165 dB or so. You think at 165 meters it cannot be heard? Do you ever realize how silly most of what you post is, and could be avoided if you would just think about it before hitting SUBMIT?

Posted: 11/28/2008 8:05:51 PM EDT

[#48]

Quoted:

Most people don't perceive sounds in the logarithmic scale format.

Then why even measure in decibels? As long as you are comfortable saying "The bushwhacker is a 32dB can" you should be comfortable with other companies expressing their NSR in a logarithmic fashion. There's really no difference in saying "30dB reduction" vs "97% reduction in sound pressure level." Just different scientific ways of saying the exact same thing.

You are such a troll...

Foolishly supporting AAC's CRAP with your own idiotic comments AND belittling Green0's statements with BS is just asinine. Give it up, would you please?

AAC LOVES to use misleading figures, even if somehow they are tied to reality. Opening your mouth about things such as this is just proving to some people what a lot of us already know...

Quoted:
Sorry Matt I didn't mean to get crappy but some of those statements are just insulting- I don't know who learned decibel logarithms in 10th grade...

Your statement was the only insulting one. While green0 and that other fella were disagreeing with each other, you are the only one who had to chime in with insults and fabrications.

green0, I don't want to use any more quotes in this post (1 is too many imo), but you made mention that majority of folks wouldn't think a suppressor had a 97% reduction, but maybe a 50% reduction. Do you honestly think those same people would be able to more efficiently rate the suppressor's dB, saying it was 30db less than 15 or 50? If someone doesn't understand exponents, they are not going to understand dB, and as such will not be able to give any kind of worthwhile estimate any better than they could rate a percentage reduction.

Renegade X, beautifully put. It should be apparent to anyone, especially a 'suppressor engineer' that your average 5.56 "M4" will be heard from distances greater than 165 meters.

Guys, it's ok to just READ! You don't have to submit posts and cross your fingers that what you said is true! No one cares about your post count!

Posted: 11/28/2008 9:06:14 PM EDT

[#49]

Quoted:
You are such a troll...

Foolishly supporting AAC's CRAP with your own idiotic comments AND belittling Green0's statements with BS is just asinine. Give it up, would you please?

AAC LOVES to use misleading figures, even if somehow they are tied to reality. Opening your mouth about things such as this is just proving to some people what a lot of us already know...

IS this the pot calling the kettle black or what? MAND, everytime you jump in a thread its AAC bad . . . . . Anyone and EVERYONE else good.

What I wonder is why you haven't been given the flick yet?

Posted: 11/29/2008 6:28:02 PM EDT

[#50]

Quoted:

Quoted:

I think every meter distant from the source should yield about a 1DB drop.

So a typical 5.56 unsuppressed firearm is 165 dB or so. You think at 165 meters it cannot be heard? Do you ever realize how silly most of what you post is, and could be avoided if you would just think about it before hitting SUBMIT?

LOL, I saw that too renegade.

Honestly, I'm not surprised idiots exist on the internet.
The problem is when they go around acting like 'professionals' and other uninformed people take that information as truth.

Green0: http://hyperphysics.phy-astr.gsu.edu/hbase/Acoustic/invsqs.html

[ARCHIVED THREAD] - Actual Noise Reduction of a 5.56 suppressor???? (Page 1 of 2)

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