Disappointed in new can

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ducati
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Disappointed in new can

Post by ducati » Sun Oct 28, 2018 6:45 pm

Because it's been sitting in our store for years, my boss gave me an AAC Eco9.

It's an older can, but reviews are reasonable, and videos make it sound quiet.

I just took it out today, and this thing is loud. Like, you-used-supers-you-idiot loud. I thought I had a case of 147grn 9mm, but I tossed the box, and poured it into an ammo can, so who knows?
Nope. Very supersonic. Fine. I can fix this.

Grabbed a box of Lawman 147grn round nose. Supposed to be 985fps. Nope Not supersonic loud, but damn near.

What's the deal? Host is a M&P CORE, 5 inch barrel. I'll try something else tomorrow, but for now -- what gives? It's a brand new can, so I know it's not damaged or shot out.

It's 68 degrees outside, and in the basement. 1,200 feet ASL in Atlanta. Subs should be sub. There's no way this is right.

I'll give AAC a call tomorrow, but in the meantime, does anyone have any ideas?

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Re: Disappointed in new can

Post by quiettime » Mon Oct 29, 2018 5:40 am

How many rounds have you put through it? A layer of carbon often does a lot for the tone of a can and a little for the volume.

You can try shooting it wet also.

Some ammo is loud. Hush ammo has made a name for themselves you might try a box of that.

Mostly though, expectations play the biggest part. No "econo" can will ever equal the performance of a flagship cam from a top manufacturer.

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Re: Disappointed in new can

Post by doubloon » Mon Oct 29, 2018 8:21 am

ducati wrote:... in the basement. ...
You're shooting in the basement?
http://www.youtube.com/watch?v=BDtd2jNIwAU MUSAFAR!
http://www.youtube.com/watch?v=8CrOL-ydFMI This is Water DavidW
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Re: Disappointed in new can

Post by fishman » Mon Oct 29, 2018 1:58 pm

videos make it sound quiet.
this means ABSOLUTELY nothing.
Last edited by fishman on Mon Oct 29, 2018 2:07 pm, edited 1 time in total.
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Re: Disappointed in new can

Post by ducati » Mon Oct 29, 2018 1:59 pm

It's a big basement! Plus 30 inches of phonebooks for a target.

This isn't my first can, and I've got under 200 rounds through it from conjugal visits in the last year.

I specifically use 147 grain rounds listed at 985 fps, so there shouldn't be any chance of environment bringing the rounds supersonic.

I'm looking for a loud "thwack" instead of a medium "bang!".

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Re: Disappointed in new can

Post by doubloon » Mon Oct 29, 2018 3:54 pm

ducati wrote:It's a big basement! ...
My suppressors sound quite loud in indoor ranges which are about 60ftx90ft.
http://www.youtube.com/watch?v=BDtd2jNIwAU MUSAFAR!
http://www.youtube.com/watch?v=8CrOL-ydFMI This is Water DavidW
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Re: Disappointed in new can

Post by Capt. Link. » Tue Oct 30, 2018 1:13 pm

Are you 100% positive that its assembled correctly with the right baffles blast baffles often have Dater Holes.Are you using a Nielsen device some are loud.Have you changed ammo or host weapons.Suppressors always sound louder to the shooter ask someone to act as a monitor.

NOS stock sometimes have mismatched parts because salesmen or customers swap them. Sorry for the nube questions but basic things have a way of being overlooked.

-CL
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Re: Disappointed in new can

Post by Racer 27 » Tue Oct 30, 2018 11:48 pm

My Tundra outside in the middle a field is pretty quite. In a indoor range, with the loud ventilation system and ear muffs, is loud!

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Re: Disappointed in new can

Post by gsyoung54 » Wed Oct 31, 2018 3:18 pm

Go shoot it outside. Federal American Eagle 147 subsonic ammo sucks... it's inherently loud. You have a good platform for testing suppressors, it's what Tyler from Silencer Shop uses a lot of the time in his videos. I think it's that you are shooting it inside. Even shooting outside at the range, which is in a huge pit, sounds loud compared to getting up on an open field and shooting. I like shooting my cans wet and usually use RemOil sprayed on the blast baffle and then down the tube at the notches in the baffles... the notches allow for the RemOil to get all over the baffles when you rotate the can back and forth, I roll spin my cans in my hands to let centrifugal force get the ablative all over. You can use wire pulling gel also, just be sure to get the blast baffle wet and get the gel down the notches in the baffles, which should all be lined up.
Don't use 124 grain sub ammo, it's near useless and as I was shooting up the last of mine last night in the cold (about 23 degrees F) many of them went supersonic. I believe cold air is denser and lowers the speed of sound. Find yourself some Fiocchi or S & B 158 grain subsonic ammunition. I now can get IMI - Israeli Military Arms - 158 grain subs but they are more expensive than the other two I listed. To me the S & B and IMI ammo are the quietest. If you can find and afford it the HUSH specialty subsonic ammunition made by Freedom Arms in 165 grain is absolutely the quietest subsonic 9 short of reloading your own. I live in Alaska and it costs me a bit to have it special ordered as no one carries in in stock yet... If you live in the contiguous 48 states I think you can order it direct from the factory and have it shipped UPS ground right to your door.
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Re: Disappointed in new can

Post by quiettime » Thu Nov 01, 2018 5:50 am

ducati wrote:
I specifically use 147 grain rounds listed at 985 fps, so there shouldn't be any chance of environment bringing the rounds supersonic.

I'm looking for a loud "thwack" instead of a medium "bang!".
There's more to quiet ammo than just velocity. Different powders burn differently and can have a very noticeable effect on report

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Re: Disappointed in new can

Post by gsyoung54 » Thu Nov 01, 2018 3:55 pm

quiettime wrote:
ducati wrote:
I specifically use 147 grain rounds listed at 985 fps, so there shouldn't be any chance of environment bringing the rounds supersonic.

I'm looking for a loud "thwack" instead of a medium "bang!".
There's more to quiet ammo than just velocity. Different powders burn differently and can have a very noticeable effect on report

There are a few 147 grain subsonic cartridges that are just plain noisy and bad in suppressors. Federal's American Eagle 147 gr. subsonic and their older 124 gr. subsonic are two examples of subsonic cartridges that just suck. And again, if you are shooting in a basement or any enclosed area... even in a pit at a shooting range you will often get much unwanted echo or the sound just doesn't have anywhere to go. The platform for the suppressor can make a huge difference. I think you were using a M&P which is a good one. Try a Sig P226 if you can or a 1911 in 9mm.
Read my last comment posted in this thread and stick with the ammo that I have thoroughly tested on many handgun platforms with many suppressors.
PPU or IMI 158 grains are the best you can usually get off the shelf with the Fiocchi 158 being a very close second, unless you are lucky enough to find some Hush 165... it's kind of the gold standard if your gun will cycle it properly. It's really subgun ammo but my full sized, clean and lightly lubed handguns eat it up.
You may need to hand-load to get the effect you are looking for but follow documented loads with your choice of bullet and powder... don't get a projectile stuck in your barrel. It's not the end of the world unless you don't notice it and fire another round.
George from Alaska

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Re: Disappointed in new can

Post by Racer » Fri Nov 02, 2018 1:53 am

Shooting inside an enclosed room will make any suppressor "sound" louder. The reason is that the brain senses that the sound duration is longer and it interprets that as louder. The duration of the sound is greater in an enclosure due to sound reflecting off the ceiling, walls, and floor. Note that the peak sound intensity (what is measured in suppressor performance) is NOT higher in an enclosed room as that would violate the laws of physics, but the brains "adds" a sensing of loudness due to the significantly increased duration.

Try shooting your suppressor outside in an open field and it will sound much quieter to your ears.
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Re: Disappointed in new can

Post by ducati » Mon Nov 12, 2018 7:02 pm

Well, I sent it off to AAC and it just returned today.

From what I can see, they did nothing at all. Just shrugged and sent it back.
Spoke with CS, and she says there's no notes at all, and the tech that looked at it is now on vacation.

All I have is the American Eagle 124 subsonic and some Speer Lawman 147 subs.

Even shooting outside is not good. Hearing safe, I suppose, but not what I'm looking for.

I'll track down some 158 & see what happens.

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Re: Disappointed in new can

Post by gsyoung54 » Mon Nov 12, 2018 10:21 pm

ducati wrote:Well, I sent it off to AAC and it just returned today.

From what I can see, they did nothing at all. Just shrugged and sent it back.
Spoke with CS, and she says there's no notes at all, and the tech that looked at it is now on vacation.

All I have is the American Eagle 124 subsonic and some Speer Lawman 147 subs.

Even shooting outside is not good. Hearing safe, I suppose, but not what I'm looking for.

I'll track down some 158 & see what happens.
There is nothing wrong with your suppressor ! When I got into suppressors big time about 5 years ago, I used to be into it 30 years ago but then had a family and a busy job and all of that, I discovered the American Eagle 147 grain subsonic ammunition and shot it all the time. It was the heaviest of the very few offerings of subsonic ammunition I could find short of reloading my own. Since I had moved 400 miles away from my reloading bench to help my ailing father in the town where I grew up I didn't have the ability to reload, I'm trying to fix that now.
What I have since discovered is that the American Eagle 147 grain subsonic load is the absolute noisiest subsonic ammunition I have ever heard in my life with the exception of the American Eagle 124 grain so called subsonic which often goes supersonic in full sized pistols and sub guns or sbr 9's especially in the cold. Cold = lower threshold for staying under supersonic velocities.
I never shoot hollow points in my pistol supressor because for a number of reasons they can start to expand in the supressor and then you get baffle and/or end cap strikes.
Have you tried about 15cc of water or some spray lithium foamy grease in your suppressor yet? Shooting wet is the way to go if you are chasing quiet with older and newer cans.
Find some of the 158 grain IMI, PPU or Fiochhi and you may be surprised. Load 5 of the 158's in your mag first followed by your American Eagle. The eagle will shoot first and you should notice a huge difference when you get to the 158's. If you have a little money you absolutely have to try some of Freedom Munitions HUSH 9mm in 158 and 165. The 165 is really sub gun ammo but functions fine in the more expensive heavy metal guns like the 1911 9mm or a Browning Hi-Power or a Sig P226 or a MK-25.
So in summary.... you are not ever going to get movie quiet unless you spend money and get a gun with a slower dwell/lock time than most inexpensive plastic guns, a long dedicated 9mm supressor, use of ablatives and get the heck outside...
Best of luck.
Last edited by gsyoung54 on Tue Nov 13, 2018 1:03 am, edited 1 time in total.
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Re: Disappointed in new can

Post by ECCO Machine » Tue Nov 13, 2018 12:24 am

ducati wrote: All I have is the American Eagle 124 subsonic and some Speer Lawman 147 subs.
AE is s--t, Lawman is OK stuff. Stick to the Speer ammo if you're not gonna handload or buy boutique stuff like the hush.
Racer wrote:Shooting inside an enclosed room will make any suppressor "sound" louder. The reason is that the brain senses that the sound duration is longer and it interprets that as louder. The duration of the sound is greater in an enclosure due to sound reflecting off the ceiling, walls, and floor. Note that the peak sound intensity (what is measured in suppressor performance) is NOT higher in an enclosed room as that would violate the laws of physics, but the brains "adds" a sensing of loudness due to the significantly increased duration.

Try shooting your suppressor outside in an open field and it will sound much quieter to your ears.
Impulse sound meters say otherwise.

It doesn't violate any physics laws; pressure in an enclosed area is greater than pressure without constriction. There's a reason milspec calls for specific distance and microphone orientation, and you will get very different numbers if you deviate from that. Pressure attenuates as it gets further from point of origin; sound pressure is no exception. The attenuation is less if it has less space to expand into. Our own eardrums work on pressure, and noises that are painful outdoors can be enough to actually rupture them in an enclosed space, such as uncorked exhaust on an engine.

You will absolutely see higher numbers indoors than outdoors. By how much depends on many things, but what I can tell you from personal experience is that the greater the exit pressure of the round, the greater the change indoors to outdoors. Think ~1 db for .22 rifle, 5-7 dB for handguns and as much as 10 dB with centerfire rifle.
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Re: Disappointed in new can

Post by Racer » Thu Nov 15, 2018 3:38 am

ECCO Machine wrote:
ducati wrote: All I have is the American Eagle 124 subsonic and some Speer Lawman 147 subs.
AE is s--t, Lawman is OK stuff. Stick to the Speer ammo if you're not gonna handload or buy boutique stuff like the hush.
Racer wrote:Shooting inside an enclosed room will make any suppressor "sound" louder. The reason is that the brain senses that the sound duration is longer and it interprets that as louder. The duration of the sound is greater in an enclosure due to sound reflecting off the ceiling, walls, and floor. Note that the peak sound intensity (what is measured in suppressor performance) is NOT higher in an enclosed room as that would violate the laws of physics, but the brains "adds" a sensing of loudness due to the significantly increased duration.

Try shooting your suppressor outside in an open field and it will sound much quieter to your ears.
Impulse sound meters say otherwise.

It doesn't violate any physics laws; pressure in an enclosed area is greater than pressure without constriction. There's a reason milspec calls for specific distance and microphone orientation, and you will get very different numbers if you deviate from that. Pressure attenuates as it gets further from point of origin; sound pressure is no exception. The attenuation is less if it has less space to expand into. Our own eardrums work on pressure, and noises that are painful outdoors can be enough to actually rupture them in an enclosed space, such as uncorked exhaust on an engine.

You will absolutely see higher numbers indoors than outdoors. By how much depends on many things, but what I can tell you from personal experience is that the greater the exit pressure of the round, the greater the change indoors to outdoors. Think ~1 db for .22 rifle, 5-7 dB for handguns and as much as 10 dB with centerfire rifle.
The suppressor/gun does not know if it is inside a room or in an open field. It produces the same amount of sound energy no matter where it is located. I agree that you can get a variety of measured energy readings depending on where you place the microphone/meter and that is why there are standards for testing. That said, the change in readings is not due to the suppressor/gun producing more energy just because it is in an enclosure. The change in meter readings must be due to other factors.
Dave

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Re: Disappointed in new can

Post by SuthDet » Thu Nov 15, 2018 11:39 pm

Racer wrote:
ECCO Machine wrote:
ducati wrote: All I have is the American Eagle 124 subsonic and some Speer Lawman 147 subs.
AE is s--t, Lawman is OK stuff. Stick to the Speer ammo if you're not gonna handload or buy boutique stuff like the hush.
Racer wrote:Shooting inside an enclosed room will make any suppressor "sound" louder. The reason is that the brain senses that the sound duration is longer and it interprets that as louder. The duration of the sound is greater in an enclosure due to sound reflecting off the ceiling, walls, and floor. Note that the peak sound intensity (what is measured in suppressor performance) is NOT higher in an enclosed room as that would violate the laws of physics, but the brains "adds" a sensing of loudness due to the significantly increased duration.

Try shooting your suppressor outside in an open field and it will sound much quieter to your ears.
Impulse sound meters say otherwise.

It doesn't violate any physics laws; pressure in an enclosed area is greater than pressure without constriction. There's a reason milspec calls for specific distance and microphone orientation, and you will get very different numbers if you deviate from that. Pressure attenuates as it gets further from point of origin; sound pressure is no exception. The attenuation is less if it has less space to expand into. Our own eardrums work on pressure, and noises that are painful outdoors can be enough to actually rupture them in an enclosed space, such as uncorked exhaust on an engine.

You will absolutely see higher numbers indoors than outdoors. By how much depends on many things, but what I can tell you from personal experience is that the greater the exit pressure of the round, the greater the change indoors to outdoors. Think ~1 db for .22 rifle, 5-7 dB for handguns and as much as 10 dB with centerfire rifle.
The suppressor/gun does not know if it is inside a room or in an open field. It produces the same amount of sound energy no matter where it is located. I agree that you can get a variety of measured energy readings depending on where you place the microphone/meter and that is why there are standards for testing. That said, the change in readings is not due to the suppressor/gun producing more energy just because it is in an enclosure. The change in meter readings must be due to other factors.

Energy produced is the same, yes. But the pressure can't dissipate as quickly. So, the sound pressure levels drop off much slower than they do outside. Not to mention that you can, and do, get extra sound from reflections that would normally be projected forward from the muzzle.

Shooters ear numbers will match mil spec numbers, instead of being 5-10db quieter like they are outside (bolt action).

A large enough space negates this, such as a 100yd indoor range, or low enough pressure and volume, like sub sonic 22lr.

Even a simple awning can make a significant difference at shooter experience.

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Re: Disappointed in new can

Post by ECCO Machine » Sat Nov 17, 2018 3:15 am

Racer wrote:
The suppressor/gun does not know if it is inside a room or in an open field. It produces the same amount of sound energy no matter where it is located. I agree that you can get a variety of measured energy readings depending on where you place the microphone/meter and that is why there are standards for testing. That said, the change in readings is not due to the suppressor/gun producing more energy just because it is in an enclosure. The change in meter readings must be due to other factors.
You'll pick up higher dBs on the mic in an enclosed area for the same reason your ears do. No, the SPL at muzzle is no different, but we don't measure right at muzzle, nor do we put our ears there unless one is a complete moron. What is higher is the SPL at any distance from the muzzle when there is less space for the pressure to attenuate.

Your contention was
Racer wrote:the peak sound intensity (what is measured in suppressor performance) is NOT higher in an enclosed room as that would violate the laws of physics,
The peak intensity as we measure it, 1 meter left of muzzle, 1.6m off the ground, with microphone vertical, does attenuate from what it is right at muzzle. How much it attenuates depends on environmental factors, and that includes walls & ceilings that constrain. There are reasons for MIL-STD-1474D:

5.4.5 Transducer locations

For shoulder-fired and hand-held weapons, transducers
shall be located at the center of each operator or
crewmember's probable head location. For other weapons
the transducer shall be positioned 1.60 m above the
ground surface; for sitting locations it shall be 80 cm above
the seat. When the operator must be present, the
measurement shall be made 15 cm from the ear closest to
the noise source (i.e., muzzle or breech, as the case may
be) on a line between the operator's ear and the noise
source.
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Re: Disappointed in new can

Post by Racer » Wed Nov 21, 2018 2:35 am

You'll pick up higher dBs on the mic in an enclosed area for the same reason your ears do. No, the SPL at muzzle is no different, but we don't measure right at muzzle, nor do we put our ears there unless one is a complete moron. What is higher is the SPL at any distance from the muzzle when there is less space for the pressure to attenuate.
Good explanation.
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Re: Disappointed in new can

Post by doubloon » Thu Nov 29, 2018 11:14 am

Racer wrote:
ECCO Machine wrote:
ducati wrote: All I have is the American Eagle 124 subsonic and some Speer Lawman 147 subs.
AE is s--t, Lawman is OK stuff. Stick to the Speer ammo if you're not gonna handload or buy boutique stuff like the hush.
Racer wrote:Shooting inside an enclosed room will make any suppressor "sound" louder. The reason is that the brain senses that the sound duration is longer and it interprets that as louder. The duration of the sound is greater in an enclosure due to sound reflecting off the ceiling, walls, and floor. Note that the peak sound intensity (what is measured in suppressor performance) is NOT higher in an enclosed room as that would violate the laws of physics, but the brains "adds" a sensing of loudness due to the significantly increased duration.

Try shooting your suppressor outside in an open field and it will sound much quieter to your ears.
Impulse sound meters say otherwise.

It doesn't violate any physics laws; pressure in an enclosed area is greater than pressure without constriction. There's a reason milspec calls for specific distance and microphone orientation, and you will get very different numbers if you deviate from that. Pressure attenuates as it gets further from point of origin; sound pressure is no exception. The attenuation is less if it has less space to expand into. Our own eardrums work on pressure, and noises that are painful outdoors can be enough to actually rupture them in an enclosed space, such as uncorked exhaust on an engine.

You will absolutely see higher numbers indoors than outdoors. By how much depends on many things, but what I can tell you from personal experience is that the greater the exit pressure of the round, the greater the change indoors to outdoors. Think ~1 db for .22 rifle, 5-7 dB for handguns and as much as 10 dB with centerfire rifle.
The suppressor/gun does not know if it is inside a room or in an open field. It produces the same amount of sound energy no matter where it is located. I agree that you can get a variety of measured energy readings depending on where you place the microphone/meter and that is why there are standards for testing. That said, the change in readings is not due to the suppressor/gun producing more energy just because it is in an enclosure. The change in meter readings must be due to other factors.
On another forum, in another life, people with meters and the initiative to actually compare indoor readings to outdoor readings there is no difference in the initial and highest impulse reading at 1m whether indoors or out.

But it absolutely sounds louder to your ear indoors than the peak impulse that gets recorded to the meter. This is because the second impulse bouncing off any walls is going to be lower in pressure and get to the meter later than 20ms.

You ear isn't capable of filtering sound on a 20ms impulse window. It's all about that reverberation.

For a practical and educational example of the difference between impulse and reverberated sound here's a little video where the use of an anechoic chamber does a good job of simulating what a meter detects as the first impulse.

If anything it begs the question as to whether or not a larger sample window might be more useful for setting real world expectations.

https://www.youtube.com/watch?v=zq07ZFMvo-c
http://www.youtube.com/watch?v=BDtd2jNIwAU MUSAFAR!
http://www.youtube.com/watch?v=8CrOL-ydFMI This is Water DavidW
Complete Form 1s http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895

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Re: Disappointed in new can

Post by doubloon » Sat Dec 01, 2018 10:40 am

Smarter Every Day just put out a follow up video to his observations on the supersonic shock waves created by subsonic projectiles that illustrates reverberated shock waves very well.

https://www.youtube.com/watch?time_cont ... AR4yTYslkk
http://www.youtube.com/watch?v=BDtd2jNIwAU MUSAFAR!
http://www.youtube.com/watch?v=8CrOL-ydFMI This is Water DavidW
Complete Form 1s http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895

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Re: Disappointed in new can

Post by dozermac » Sat Dec 01, 2018 1:34 pm

All this talk about ammo, powder, ranges, etc is rubbish for this guy. I’ve been doing this since Cara and Kevin answered the phones at AAC themselves and I have a lot of cans including this one. It’s loud and that’s all there is to it. You just have to deal

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Re: Disappointed in new can

Post by SuthDet » Sun Dec 02, 2018 10:23 am

doubloon wrote:
Racer wrote:
ECCO Machine wrote:
AE is s--t, Lawman is OK stuff. Stick to the Speer ammo if you're not gonna handload or buy boutique stuff like the hush.



Impulse sound meters say otherwise.

It doesn't violate any physics laws; pressure in an enclosed area is greater than pressure without constriction. There's a reason milspec calls for specific distance and microphone orientation, and you will get very different numbers if you deviate from that. Pressure attenuates as it gets further from point of origin; sound pressure is no exception. The attenuation is less if it has less space to expand into. Our own eardrums work on pressure, and noises that are painful outdoors can be enough to actually rupture them in an enclosed space, such as uncorked exhaust on an engine.

You will absolutely see higher numbers indoors than outdoors. By how much depends on many things, but what I can tell you from personal experience is that the greater the exit pressure of the round, the greater the change indoors to outdoors. Think ~1 db for .22 rifle, 5-7 dB for handguns and as much as 10 dB with centerfire rifle.
The suppressor/gun does not know if it is inside a room or in an open field. It produces the same amount of sound energy no matter where it is located. I agree that you can get a variety of measured energy readings depending on where you place the microphone/meter and that is why there are standards for testing. That said, the change in readings is not due to the suppressor/gun producing more energy just because it is in an enclosure. The change in meter readings must be due to other factors.
On another forum, in another life, people with meters and the initiative to actually compare indoor readings to outdoor readings there is no difference in the initial and highest impulse reading at 1m whether indoors or out.

But it absolutely sounds louder to your ear indoors than the peak impulse that gets recorded to the meter. This is because the second impulse bouncing off any walls is going to be lower in pressure and get to the meter later than 20ms.

You ear isn't capable of filtering sound on a 20ms impulse window. It's all about that reverberation.

For a practical and educational example of the difference between impulse and reverberated sound here's a little video where the use of an anechoic chamber does a good job of simulating what a meter detects as the first impulse.

If anything it begs the question as to whether or not a larger sample window might be more useful for setting real world expectations.

https://www.youtube.com/watch?v=zq07ZFMvo-c

In a small enough space, it will be louder.
Over a table or under an awning, it will be louder.

Propper sound meters (2209, pulse) don't lie.

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Re: Disappointed in new can

Post by doubloon » Sun Dec 02, 2018 6:16 pm

SuthDet wrote:...

In a small enough space, it will be louder.
Over a table or under an awning, it will be louder.

Propper sound meters (2209, pulse) don't lie.
Sound only travels directly away from the source until it reaches some impediment to it's journey.

If the space is small enough that the reverberation or echo off a barrier reaches the mic before the time window ends then it may seem louder but the original sound is not louder. It may seem louder because multiple impulses were recorded in the same time window.

There is still some distance that must be covered 2X between the mic and whatever barrier creates the echo or reverberation.

Sound waves deteriorate and lose energy over distance, they do no accumulate energy over distance.

If it were possible for a sound wave to increase in energy over distance or increase in energy as a result of being bounced off a tin roof the energy problems of the world would be solved and other energy sources would be obsolete.

Physics doesn't lie.

I think the meter used in the other place is Larson-Davis 800B with a B&K 4938 mic.
http://www.youtube.com/watch?v=BDtd2jNIwAU MUSAFAR!
http://www.youtube.com/watch?v=8CrOL-ydFMI This is Water DavidW
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SuthDet
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Re: Disappointed in new can

Post by SuthDet » Mon Dec 03, 2018 12:52 am

doubloon wrote:
SuthDet wrote:...

In a small enough space, it will be louder.
Over a table or under an awning, it will be louder.

Propper sound meters (2209, pulse) don't lie.
Sound only travels directly away from the source until it reaches some impediment to it's journey.

If the space is small enough that the reverberation or echo off a barrier reaches the mic before the time window ends then it may seem louder but the original sound is not louder. It may seem louder because multiple impulses were recorded in the same time window.

There is still some distance that must be covered 2X between the mic and whatever barrier creates the echo or reverberation.

Sound waves deteriorate and lose energy over distance, they do no accumulate energy over distance.

If it were possible for a sound wave to increase in energy over distance or increase in energy as a result of being bounced off a tin roof the energy problems of the world would be solved and other energy sources would be obsolete.

Physics doesn't lie.

I think the meter used in the other place is Larson-Davis 800B with a B&K 4938 mic.

I agree, the source is no louder.

But I disagree with the idea that you're hearing the reverberation to think it is louder.

The source is the same, but indoor, the pressure does not dissipate as quickly.

In a small space (maybe a 12x20 shed) the muzzle and shooter's ear numbers will be nearly identical, and they will be louder than in an open space.

I'm not 100% sure why, I'd like to think that the muzzle blast is enough to increase the pressure in the entire room and allow the pressure wave to carry less impeded, but I'm unsure how to test for that.

In short, in a small space (whether fully enclosed or only on a few sides), it will sound louder, and the spl you experience will be higher, and the risk of damage will be higher.

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