Sound level question

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__steve__

__steve__

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Given two different loads of same caliber, pressure, and type of powder, for example 500 S&W magnum’s both at 58,000 PSI, where the difference is one is a 400 grain traveling at 1900 fps, and the other is 650 grain at 1200 fps, would they both produce the same level of sound or would the supersonic one be much louder?
 
I find that interesting because in a pistol I think the gas would still be as loud where in a rifle the pressure would have dropped before the projectile left the barrel. Really quiet guns are run with faster powders for that reason but I don't have the full answer
 
Trying to figure out a perfect bear load to use for the 500, one that would not damage my hearing anymore than it already is if I had to fire one. I usually use foam plugs and headsets together. I once had just the ear plugs in and forgot the headset, what a mistake.
 
Let me guess....you're taking a new shooter to an indoor range, and want to punish (or impress) someone real good?...?....?

From my experience (in 357 magnum, 44 magnum)
Essentially small versions of the 500 S&W mag you mention, lighter bullets going faster produce more noise than heavier bullets going slower, with respect to both being maximum published data for the respective weight bullet.....
For example 44mag w/ 180gr XTP and 31.5gr of W296 going 1,700 fps is definitely louder than the 240gr XTP and 24gr of W-296 going 1,450.

Same is True for 357 when loading 110gr over 24gr of W296 vs say a 158gr over 16gr of W-296.

More powder is used to achieve a similar pressure value, but higher velocity for the lighter bullet. More propellant gases expanding the air outward beyond the muzzle tip can create more muzzle blast, thus louder report. The lighter bullet loads seem quite violent, producing very quick, sharp recoil and a very loud boom, I'd hate to fire an S&W 500 "equivalent" of my above mentioned loads....44 Mag must feel like shooting a .22 after that!

Both 1) Muzzle blast will be more due to more air being accelerated outward and 2) air pressure wave created by the faster bullet will create more noise. The same diameter bullet, assuming they have similar nose profiles, the faster one has to move air out of the way quicker, thus higher air compression wave ahead of the projectile....that equates to more noise too.
 
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__steve__ said:
Trying to figure out a perfect bear load to use for the 500, one that would not damage my hearing anymore than it already is if I had to fire one. I usually use foam plugs and headsets together. I once had just the ear plugs in and forgot the headset, what a mistake.
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I think either one would do less damage than the bear.
Are we talking brown bear or white? Can't be talking black bears. A .357Mag will take a black bear at danger range.
 
Palladan44 said:
Let me guess....you're taking a new shooter to an indoor range, and want to punish (or impress) someone real good?...?....?
.
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No, but now that you mentioned it haha

Was just interested in what load would have the most impact energy with the least noise if I were to carry the 500 4” in the mountains. If I managed to stop an attacking bear, hearing damage would be certain, and wearing ear plugs all day just in case isn’t feasible. It would still be very loud without ear protection, just not quite as loud
 
In your scenario there is no significant difference with regards to hearing damage. That is all about the muzzle blast, super or sub makes no difference, and there is NO SUCH BEAST AS A HEARING SAFE UNSUPPRESSED BIG BORE HANDGUN. You're choices are ear pro (for hunting I use electronic buds so I can hear) or ditch the wheel gun and move to a big bore pistol and use a suppressor, switch to a suppressed long gun, or build a SBR and suppress it. It will still be hearing safe suppressed, even super. Your best option with what you have is to drop the coin on electronic ear buds...trying to reduce hearing damage with reduced loads in a revolver is a completely unachievable goal.
 
higgite said:
Both of your examples are supersonic. But to answer your basic question, the report of a supersonic bullet is louder than that of a subsonic bullet.
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Well, not exactly. The supersonic round has two reports. The muzzle blast, and when it cracks. The crack of exceeding the speed of sound isn't relevant to hearing damage. This is why shooting high power rifles suppressed is still hearing safe, the muzzle blast is reduced, the crack remains. The muzzle blast is what causes hearing damage.
 
If it can stop a bear it’ll hurt your ears. If we’re stray dogs, a subsonic 45 or 38 would be a quiet option, but bigger bears and subsonic means mountain howitzer territory.

The hearing risk for a bear defense load seems like a calculated risk to me. Seeing a bear is rare. I’ve seen one ever hiking in upstate SC. He wanted nothing to do with us and was a black hairy landslide running away. A hostile run in is so unlikely I’d risk the hearing damage. Pepper spray , dogs and loud bells keep them away too.
 
I'd rather relate the story of how I lost my hearing than have my girlfriend tell how the bear used my femor to clean his teeth...
Ear buds are new ish and you might want to spend your efforts figuring out which type is your best option.
 
My experience any short barrel gun is going to hurt your ears if not protected, even a the small 22LR. I've used the electronic ear muffs for decades, work great. I've switched over to custom ear plugs for convenience. The custom ear pugs are a sonic valve stopping the precaution that hurts your ear. It allows you to hear normally with only a small 4 db dampening. Cost around $200, most hearing places can take a mold impression for fit.
 
EricBu said:
Well, not exactly. The supersonic round has two reports. The muzzle blast, and when it cracks. The crack of exceeding the speed of sound isn't relevant to hearing damage. This is why shooting high power rifles suppressed is still hearing safe, the muzzle blast is reduced, the crack remains. The muzzle blast is what causes hearing damage.
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So, you're answer to OP's question is that muzzle blast plus supersonic crack doesn't make the report louder than subsonic muzzle blast alone? The OP didn't mention suppressed high power rifles, so I figured he was talking about unsuppressed firearms, probably pistols. But, I could have misread it. :)
 
higgite said:
So, you're answer to OP's question is that muzzle blast plus supersonic crack doesn't make the report louder than subsonic muzzle blast alone? The OP didn't mention suppressed high power rifles, so I figured he was talking about unsuppressed firearms, probably pistols. But, I could have misread it. :)
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I understand the OP’s question completely. If you live where humans are invading bears habitat and they are getting aggressive then bringing the most gun feasible is not a terrible idea. Only thing is I have had several audiologists tell me straight up it’s the hypersonic crack that damages hearing long term and the air compression boom is only temporary. I have to think they know best and suggest the OP consult a certified doctor of audiology for an authoritative opinion.
If a bear encounter can be avoided, avoid it. If it can’t, swift action and accuracy with a lesser bullet will trump big bullets and a loud miss every time.
 
higgite said:
So, you're answer to OP's question is that muzzle blast plus supersonic crack doesn't make the report louder than subsonic muzzle blast alone? The OP didn't mention suppressed high power rifles, so I figured he was talking about unsuppressed firearms, probably pistols. But, I could have misread it. :)
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No, it does not, not in respect to hearing safe shooting. And again, to correct you...it's two separate sounds, one following the other, you keep treating it as a single event, two events, two physical processes. A supersonic round has a muzzle blast, followed by a supersonic crack, two sounds, occuring at 2 different times. A subsonic round has a single sound, the muzzle blast. The muzzle blast occurs in both instances, and from a hearing safe perspective, there is no meaningful difference between projectile velocity with regards to the muzzle blast. Don't know how much clearer I can be there. The dB level of the muzzle blast is related to many other factors (powder type, charge, barrel length, presence of muzzle devices, firearm type, etc)...the speed of the actual projectile is NOT one of the factors that meaningfully impacts the muzzle blast. Understand the distinction between muzzle blast and the crack of the projectile exceeding the speed of sound. Two entirely separate events, caused by two separate physical actions. Hint: All muzzle blasts are supersonic (maybe technically hypersonic) by definition, as they occur due to the rapid expansion of hot gas (an explosion), so in simple terms, the sound is created by the hot gas, NOT the projectile, the 2nd report of a supersonic round is caused by the physical resistance of air as the projectile moves through it. This is what makes a suppressor work...it channels and cools the hot gas from the muzzle blast, slowing it down and cooling it and reducing it's sound level, since the supersonic projectile crack occurs long after the projectile has left the muzzle....a suppressor has no effect on it. As I explained, it is not a louder report as you stated, it is in fact two reports. Hearing damage is caused by muzzle blast, not the supersonic crack, which is completely irrelevant to making a firearm hearing safe. The mention of high power rifles was to illustrate that making a gun hearing safe through suppression has nothing to do with whether or not the projectile is super sonic. Perhaps you're confused by the distinction between "quiet" and "hearing safe". So again, to repeat myself, super or sub have no relevant impact to making a firearm hearing safe, which was the OPs implied mission: "make a bear gun less likely to cause hearing damage". And as I already said, reducing loads won't provide a hearing safe gun, period, ever, in any way shape or form The only options are switch to something that can be suppressed, or use ear pro. For hunting, or where you're worried about a bear encounter, you need to hear. So the best ear pro choice for hunting is electronic buds. Hunting suppressed (if your state allows it) is the best solution especially long term. 2nd is invest in good ear pro.
 
EricBu said:
No, it does not, not in respect to hearing safe shooting. And again, to correct you...it's two separate sounds, one following the other, you keep treating it as a single event, two events, two physical processes. A supersonic round has a muzzle blast, followed by a supersonic crack, two sounds, occuring at 2 different times. A subsonic round has a single sound, the muzzle blast. The muzzle blast occurs in both instances, and from a hearing safe perspective, there is no meaningful difference between projectile velocity with regards to the muzzle blast. Don't know how much clearer I can be there. The dB level of the muzzle blast is related to many other factors (powder type, charge, barrel length, presence of muzzle devices, firearm type, etc)...the speed of the actual projectile is NOT one of the factors that meaningfully impacts the muzzle blast. Understand the distinction between muzzle blast and the crack of the projectile exceeding the speed of sound. Two entirely separate events, caused by two separate physical actions. Hint: All muzzle blasts are supersonic (maybe technically hypersonic) by definition, as they occur due to the rapid expansion of hot gas (an explosion), so in simple terms, the sound is created by the hot gas, NOT the projectile, the 2nd report of a supersonic round is caused by the physical resistance of air as the projectile moves through it. This is what makes a suppressor work...it channels and cools the hot gas from the muzzle blast, slowing it down and cooling it and reducing it's sound level, since the supersonic projectile crack occurs long after the projectile has left the muzzle....a suppressor has no effect on it. As I explained, it is not a louder report as you stated, it is in fact two reports. Hearing damage is caused by muzzle blast, not the supersonic crack, which is completely irrelevant to making a firearm hearing safe. The mention of high power rifles was to illustrate that making a gun hearing safe through suppression has nothing to do with whether or not the projectile is super sonic. Perhaps you're confused by the distinction between "quiet" and "hearing safe". So again, to repeat myself, super or sub have no relevant impact to making a firearm hearing safe, which was the OPs implied mission: "make a bear gun less likely to cause hearing damage". And as I already said, reducing loads won't provide a hearing safe gun, period, ever, in any way shape or form The only options are switch to something that can be suppressed, or use ear pro. For hunting, or where you're worried about a bear encounter, you need to hear. So the best ear pro choice for hunting is electronic buds. Hunting suppressed (if your state allows it) is the best solution especially long term. 2nd is invest in good ear pro.
Click to expand...
I’m sorry, I don’t have time to wade all the way through a dissertation. I thought OP’s initial post (not necessarily his followup posts) asked a pretty simple question which warranted a pretty simple answer. You disagree with my answer. My ears tell me different. Fair enough.
 
EricBu said:
No, it does not, not in respect to hearing safe shooting. And again, to correct you...it's two separate sounds, one following the other, you keep treating it as a single event, two events, two physical processes. A supersonic round has a muzzle blast, followed by a supersonic crack, two sounds, occuring at 2 different times. A subsonic round has a single sound, the muzzle blast. The muzzle blast occurs in both instances, and from a hearing safe perspective, there is no meaningful difference between projectile velocity with regards to the muzzle blast. Don't know how much clearer I can be there. The dB level of the muzzle blast is related to many other factors (powder type, charge, barrel length, presence of muzzle devices, firearm type, etc)...the speed of the actual projectile is NOT one of the factors that meaningfully impacts the muzzle blast. Understand the distinction between muzzle blast and the crack of the projectile exceeding the speed of sound. Two entirely separate events, caused by two separate physical actions. Hint: All muzzle blasts are supersonic (maybe technically hypersonic) by definition, as they occur due to the rapid expansion of hot gas (an explosion), so in simple terms, the sound is created by the hot gas, NOT the projectile, the 2nd report of a supersonic round is caused by the physical resistance of air as the projectile moves through it. This is what makes a suppressor work...it channels and cools the hot gas from the muzzle blast, slowing it down and cooling it and reducing it's sound level, since the supersonic projectile crack occurs long after the projectile has left the muzzle....a suppressor has no effect on it. As I explained, it is not a louder report as you stated, it is in fact two reports. Hearing damage is caused by muzzle blast, not the supersonic crack, which is completely irrelevant to making a firearm hearing safe. The mention of high power rifles was to illustrate that making a gun hearing safe through suppression has nothing to do with whether or not the projectile is super sonic. Perhaps you're confused by the distinction between "quiet" and "hearing safe". So again, to repeat myself, super or sub have no relevant impact to making a firearm hearing safe, which was the OPs implied mission: "make a bear gun less likely to cause hearing damage". And as I already said, reducing loads won't provide a hearing safe gun, period, ever, in any way shape or form The only options are switch to something that can be suppressed, or use ear pro. For hunting, or where you're worried about a bear encounter, you need to hear. So the best ear pro choice for hunting is electronic buds. Hunting suppressed (if your state allows it) is the best solution especially long term. 2nd is invest in good ear pro.
Click to expand...
The difference in decibels between a .32Long and .44Mag is fairly insignificant - 152.4 vs. 164.5 dB - so the argument about more powder or bigger blast doing more damage doesn’t hold much water, either. Maybe that’s just a matter of perception or the mind playing tricks on the senses but a less than 10% (12.1 dB) delta is not significant. Again, I really think the OP would benefit from a consultation with a real, trained medical doctor of audiology. Internet wisdom - even from me! :eek: - isn’t going to be useful.
 
GeoDudeFlorida said:
The difference in decibels between a .32Long and .44Mag is fairly insignificant - 152.4 vs. 164.5 dB - so the argument about more powder or bigger blast doing more damage doesn’t hold much water, either. Maybe that’s just a matter of perception or the mind playing tricks on the senses but a less than 10% (12.1 dB) delta is not significant. Again, I really think the OP would benefit from a consultation with a real, trained medical doctor of audiology. Internet wisdom - even from me! :eek: - isn’t going to be useful.
Click to expand...
That's because the dB scale is almost logarithmic not linear. More like earthquakes than an extra ounce in a beer.
What is the scale of decibel?
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On the decibel scale, the quietest audible sound (perceived near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB, 40 dB and so on.Jan 25, 2019
 
The muzzle pressure needs to be factored. The breech pressure may be 58,000 psi for any loads compared, but the muzzle pressure can vary significantly, and this is the pressure level that is popped off into the atmosphere to generate the sound level. This isn't a function of the bullet mass per se, but it depends on the powder burn rate and progressivity/digressivity, and of course on the barrel length. Generally speaking, if you want the quietest load while still having good penetration, go with a heavy-for-caliber bullet, load it with a fast-burning/digressive powder, and shoot it out of a long barrel with no muzzle brake, port or compensator. It will not be hearing safe, but it could be several decibels lower.

The heavier bullet will use less powder to achieve the same 58,000 MAP and therefore the muzzle pressure will be lower and the sound level lower.
 
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