Barrel Sound Signature

Here is a list of many barrels, from quietest to loudest 12' from the left side of the barrel


First number is 12' to the left reading second number is 12' infront of the barrel
70.93 -----72.91 PPS
71.59 -----73.44 SLY
71.62 -----75.3 Kaner
72.42 -----74.92 SP Teardrop
72.78 -----82.73 SM-1
72.81 -----76.18 Matchstik
73.12 -----74.86 Trilogy
73.19 -----84.60 Custom Products
73.45 -----79.83 Empire 7pc
73.84 -----75.78 Freak 16"
73.88 -----86.58 Empire Revolver
74.05 -----76.63 Un1Tec
74.33 -----80.73 Scepter
74.31 -----76.10 Freak 14"
74.53 -----81.81 Redz pepperstick
74.84 -----76.36 Phat
74.92 -----89.36 TI Longbow
74.96 -----81.97 Dye Ul
76.06 -----76.71 Hammerhead
77.53 -----75.06 Freak 10"
80.47 -----89.17 Pipe
And just proof that unported barrels ARE louder..
84.38 -----91.68 99 Autococker stock (unported barrel)


Here is a list of the barrels from quietest to loudest at 12' infront of the barrel.

70.93 -----72.91 PPS
71.59 -----73.44 SLY
72.84 -----73.75 Proto Stock
73.12 -----74.86 Trilogy
72.42 -----74.92 SP Teardrop
77.53 -----75.06 Freak 10"
71.62 -----75.30 Kaner
73.13 -----75.42 Xmag stock
73.84 -----75.78 Freak 16"
74.31 -----76.10 Freak 14"
74.84 -----76.36 Phat
74.05 -----76.63 Un1Tec
76.06 -----76.71 Hammerhead
73.45 -----79.83 Empire 7pc
74.33 -----80.73 Scepter
74.53 -----81.81 Redz pepperstick
74.96 -----81.97 Dye Ul
72.78 -----82.73 SM-1
73.19 -----84.60 Custom Products
73.88 -----86.58 Empire Revolver
74.69 -----87.64 JJ Edge
80.47 -----89.17 Pipe
84.38 -----91.68 99 Autococker stock (unported barrel)

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Lets come up with theories on why some are quieter than others.

Here is what I came up with,

MATERIALS

If Im correct, I did fail chemistry..

Palmers Barrel is made out of brass, known to be denser than aluminum, However next in line is the sly, and its carbon fiber known to be less dense than aluminum..

Porting & Length

Usually longer barrels are quieter, my belief is that a longer barrel allows the air that is propelling the ball more volume and we all know that when you take a pressure and give it more volume the pressure drops. Sound = pressure, thats why a silencer works, it drops the pressure thats exiting the firearm from around 1200 or so psi? to 60 psi..

Now how many ports?
How big should the ports be?
Where should the ports begin?

What do you guys think?

Using whatever knowledge you guys have... I know Tom wrote a big article about pressures in the barrel that should really help. Any imput you guys can have would help..

what was the foundation for the test? what did you use to measure the decibel levels? what gun where you using? velocity you were shooting at? ect ect, this is intriguing :)

Sorry though you saw this, its a test of many paintball barrels.

Enjoy..

http://www.pbnation.com/showthread.php?t=2218018

I thought GP used brass to make his barrels. Copper isn't practical as it's too soft and machines very poorly.

Quote:

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Originally Posted by muzungu_mbaya

I thought GP used brass to make his barrels. Copper isn't practical as it's too soft and machines very poorly.

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Im an idiot.. Your correct, I first said it was nickle remember it was brass and then went back to type brass and typed copper... Sorry.

If you can get a hold of an Ego barrel, I'd like to see that. My 08 Ego sounds like a Spyder, but when I put my MatchStik on, it quiets down a lot. However, there's a bore difference of .004 between the two, so that could be a big part of the reason.

It's funny that there don't seem to be any one piece barrels among those posted here. I think that would prove a more interesting comparison given that Palmer tops the list.

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Originally Posted by Castro #66

It's funny that there don't seem to be any one piece barrels among those posted here. I think that would prove a more interesting comparison given that Palmer tops the list.

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What one piece barrels are you wanting info on. I have more data, but unfortunately it is still in paper form. I know I did ~ a dozen 1piece ones.

edit: 6 of those are 1 piece

pps
proto stock
triliogy stock
xmag stock
untec
I cant read the post while editing, but i think i counted one more.

edit again:
autococker stock

:cheers:

length lowers the sound.

porting lowers the sound. more porting...less sound. the pps brass was ported down half of the barrel.

Ah, I suppose I thought the XMag stock was the same as the funny looking J&J I received with my Tac One. Proto and Trilogy both offer two-piece varieties with their stock guns as well. I'm not sure how I missed the UniTec, but I saw the Palmer first and wondered if it's their "elliptical boring" or whatever it is.

Funny thing too... while I haven't seen one recently, I could've sworn that Evil barrels had HUGE porting.

Quote:

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Originally Posted by MANN

length lowers the sound.

porting lowers the sound. more porting...less sound. the pps brass was ported down half of the barrel.

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sound is a pressure, expansion brings a drop in pressure a longer barrel is more volume meaning a drop in presure before the ball exits the barrel causing a lower sound signature..

Porting does not always lower the sound, too much porting and the barrel gets louder, it needs to be the right about of porting in the right spot, I figure it should begin after 5-8 inches and then have more or bigger ports the closer to the tip that it gets..

Hmm. Couple questions before these results could be considered meaningful.

How many trials did you do with each barrel? What brand of paint did you use? Did you measure the size of the balls beforehand, and if so, do you have those measurements?

I bet ball size has a lot to do with it - it would be my hypothesis that overbored paint would be louder than underbored paint.

Quote:

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Originally Posted by ThePixelGuru

Hmm. Couple questions before these results could be considered meaningful.

How many trials did you do with each barrel? What brand of paint did you use? Did you measure the size of the balls beforehand, and if so, do you have those measurements?

I bet ball size has a lot to do with it - it would be my hypothesis that overbored paint would be louder than underbored paint.

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I'm thinking these same thoughts/questions.

Nice findings regardless.

Quote:

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Originally Posted by Spencer

sound is a pressure, expansion brings a drop in pressure a longer barrel is more volume meaning a drop in presure before the ball exits the barrel causing a lower sound signature..

Porting does not always lower the sound, too much porting and the barrel gets louder, it needs to be the right about of porting in the right spot, I figure it should begin after 5-8 inches and then have more or bigger ports the closer to the tip that it gets..

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The best marker I haven't heard was a cocker with about a 16" stiffi on it. It also had some timing issues.

Without ports, if you can time a cocker so that the ball has no pressure behind it when it hits the ports or muzzle, you'll get nothing but ball. It means the ball has to be going well over the target muzzle velocity before it gets there. Accuracy probably suffers a too.

Some of Tom's barrel tech articles talk about interior deceleration of the ball. I had seen cockers like this, but it wasn't until I built a nerf launcher that I could actually put my hand on it. I had a rubber breech plug that popped out when I fired the rocket. The rocket didn't go more than a couple feet. Since it didn't come out with much force I held it in with my hand. When I fired it again, the plug pushed against my hand then sucked itself into the launcher. The nerf went about 20 feet. After a few more shots, I cut about 8 inches off of the barrel and now had about 180 fps and good distance. I still had to give up on the rubber plug though.

My point is that you can make lots of measurements, but the marker setup has a lot to do with it and needs to be recorded as well. A friend's new viking sounded like a real gun for half a day. After about a case of paint I thought he had changed markers because I didn't hear it anymore. He had not done anything to it.

Quote:

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Originally Posted by ThePixelGuru

Hmm. Couple questions before these results could be considered meaningful.

How many trials did you do with each barrel? What brand of paint did you use? Did you measure the size of the balls beforehand, and if so, do you have those measurements?

I bet ball size has a lot to do with it - it would be my hypothesis that overbored paint would be louder than underbored paint.

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used ~ 6 types of paint & reballs. we measured many of the paintballs (took a sample study).. All of this stuff is listed in the "test"

Quote:

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Originally Posted by Spider-TW

My point is that you can make lots of measurements, but the marker setup has a lot to do with it and needs to be recorded as well. A friend's new viking sounded like a real gun for half a day. After about a case of paint I thought he had changed markers because I didn't hear it anymore. He had not done anything to it.

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The sound reduction should be the same as long as the same marker is used with all barrels.

Quote:

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Originally Posted by Spider-TW

The best marker I haven't heard was a cocker with about a 16" stiffi on it. It also had some timing issues.

Without ports, if you can time a cocker so that the ball has no pressure behind it when it hits the ports or muzzle, you'll get nothing but ball. It means the ball has to be going well over the target muzzle velocity before it gets there. Accuracy probably suffers a too.
.

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I would second that. Ive seen a Freeflow that was nearly silent. All you could hear was a light *click* of the p-block. That was actually what made me fall in love with them.

Pipes have forward-angled ports intended to project sound.

crazy cool, I have to look at the whole test post, but it looks like you were fairly thorough.
any dry fire numbers in there?

I am imagining a a paintball moving down a barrel like the cone the cone of a speaker, so the sound is created by the dissipation of energy; the ball exiting and the extra gas (pressure) venting. Same size and mass paintball exiting at the same velocity should create the same dBs on its way out the barrel, right? So that would be like a base level of noise. The rest should be from the extra pressure that has to vent and where it vents from. Porting is not big enough to allow for unrestricted air flow, so a lower volume over time will exit through it then down the end of the barrel. The more high pressure gas exiting the barrel tip, the louder the barrel? Sounds plausible. Did happen to keep track of turning up/down the input pressure to the marker in relation to noise? My completely pulled out-o-the butt theory on how to make a quite barrel is as follows

longer over all length for gas to expand and pressure to drop
longer back (I believe in rule of 8")
Port after eight inches, right to the end, at least six inches of porting

Well, I've jumped to some big conclusions, anyone with a background in compressible flow on AO to help me out?

Quote:

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Originally Posted by MANN

used ~ 6 types of paint & reballs. we measured many of the paintballs (took a sample study).. All of this stuff is listed in the "test"

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I meant Spencer's test, which is separate from yours... or is this all data from the same test?

Quote:

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Originally Posted by ThePixelGuru

I meant Spencer's test, which is separate from yours... or is this all data from the same test?

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all mine. he just copied and pasted.

Quote:

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Originally Posted by MANN

all mine. he just copied and pasted.

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Yes, sorry, I did not claim this as my own, I thought I stated that somewhere..

All I did was arranged the numbers in order from least to greatest. I had no input in the tests. Never met man..

Quote:

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Originally Posted by MANN

all mine. he just copied and pasted.

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You mention the actual versus the advertised bore dimensions. I looked for it in there (pbn), but didn't see any comparisons. Did I miss it?

**edit** I forgot about post #7 while I was reading elsewhere. Maybe someday?

Also, while you have all that fresh data on ball sizes, would you be able to throw out some standard deviation numbers? I would be nice to know what the manufacturers are holding lately. :D

ALong with the Decibel measurements, Could you post up:

barrel lengths
combined porting area
bore diameter
Porting pattern

Given identical paintballs and shot from the same platform - these will be the largest factors.

Longer barrel will be quieter.
More porting is generally quieter.
As aereal desity of the porting increases near the breech it will get louder.
Too much overbore will be louder.
A lower pitched tone carries distance better than a higher pitched tone.

Quote:

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Originally Posted by Pneumagger

A lower pitched tone carries distance better than a higher pitched tone.

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True, but a higher pitch sound is easier to locate and is perceived as louder than a lower pitched tone..

True...

I much prefer the thump of a good wet .45acp suppressor to a higher pitched "quieter" 9mm suppressor even if the 9mm is by definition quieter by 3-4dB.

Well I just ordered a 16" Deadlywind barrel, I'm sure its going to be super quiet..