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All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: gandalfretlaw on August 28, 2012, 04:33:46 PM

Title: Air Gun Noise Levels
Post by: gandalfretlaw on August 28, 2012, 04:33:46 PM
I got my decibel meter and did some testing. I used a camera tripod to test with. I found that setting the range and using the record max/min mode worked best. I used the range 60-110 and found that using 80-110 gave somewhat higher results (probably because it zeroed in on louder noises faster), however I used 60 as many of the guns weren't registering at 80. For the first two rounds at ten I was trying to make sure I was getting consistent results so I used the average for computations.

The stapler gun which was not working but made the click sound fine was included for a base reference.

I'm including an image and a text file. The extension on the text file can be changed from .txt to .csv and any spreadsheet program should load it.
Title: Re: Air Gun Noise Levels
Post by: gandalfretlaw on August 28, 2012, 04:44:50 PM
One of the first things I noticed is that the air guns were about as noisy at ten feet as the stapler was in close. To me this means that there is not a significant amount of noise going outside of my backyard. The fence probably takes care of quite a lot of it.

I also see that on many guns the spring is noisier than the muzzle report. The Gamo Big Cat has a very noisy action. I remember the Whisper sounding like this but I've now put a few thousand pellets down it and it's much quieter. No doubt the Cat would get quieter with use. I don't even think it's broken in. I kinda think of it as a spare Whisper. The Air Hawk is almost certainly still dieseling. I could smell it every time after firing.

I also noticed that although none of the springers have any significant recoil, the Benji Trail does. If memory serves it has more recoil than my Remington 22 powder gun. Quite interesting. The crispness of shooting CO2 and pump is quite different from the springers, but by the end of testing I was quite tired of pumping the 312.
Title: Re: Air Gun Noise Levels
Post by: Bullit on August 28, 2012, 04:58:25 PM
It seems that the peaks are "clipped" from maximum.  Something like -20db.  IIRC, a stapler is around 96-98db.  but don't hold me fast to that exact number, I'm close.  I am referring to your 6" muzzle column, of course.  I like that you did both muzzle and trigger readings.  Well thought out.

Your observation of the spring and mechanical noise is right on target!  It is the majority of the source.
Finally, I am glad you took the time/effort to get "away" from the muzzle and actually listen and measure.  Congrats, and Thanks for Posting it!  Mike
Title: Re: Air Gun Noise Levels
Post by: gandalfretlaw on August 28, 2012, 05:21:51 PM
Others have said it and I think its true that these meters have trouble with very short sounds. Probably the more expensive ones can handle fast sounds better. The manual said that by narrowing the range you could get the meter reading the level faster. So it would make sense that reading 80-110 would produce higher readings than 60-110 when the sound is very quick. I tried 80-110 on the gamo cadet and it didn't even blip so I kept with the lower scale to maintain consistency. One thing that may have affected my stapler sound was I wasn't stapling into anything, just firing it in the air. I couldn't even get a reading on my portable drill at ten feet.

I guess I could have done ten yards but I it's not a clear area and it would probably produce echos and stuff. Ten yards in an open field is different than ten yards between a shed and house.
Title: Re: Air Gun Noise Levels
Post by: Bullit on August 28, 2012, 05:36:08 PM
Yeah, I kinda suspected it would happen, but I think You did a good job with what you have,,,for sure!!!!
Hey, you only got $13.00 into it, right?, so what the heck...add db correction to it and call it good and close buddy!
Here's a link to various A/Gs and some reference dbs that might help you. 
http://www.straightshooters.com/decibel-ranking-of-airguns.html (http://www.straightshooters.com/decibel-ranking-of-airguns.html)
Title: Re: Air Gun Noise Levels
Post by: gandalfretlaw on August 28, 2012, 06:45:30 PM
I put it a little lower than their stapler gun, between the stapler and stapler gun at 95db. This gave an adjustment of +18. I plugged it in and here are the numbers. I didn't bother to add it to the two 10' readings, only the average. I am not certain this works the way we think though as sound levels double every 6 (or 10?) decibels. Perhaps it does though.

The results do compare somewhat to the older chart. What do you think?

Yes $13 (shipping included).
Title: Re: Air Gun Noise Levels
Post by: QVTom on August 28, 2012, 06:55:56 PM
Walter, your mission should you accept...........

Measure  levels of the springers listed when the meter is located next to the shooters gun side ear.  A measurement of the action with respect to the shooter. 

Tom

Title: Re: Air Gun Noise Levels
Post by: gandalfretlaw on August 28, 2012, 07:01:17 PM
I think I did that actually. The one measurement is taken 6" from the trigger. The shooters ear is within 6" of the trigger and in the same general vicinity. You'd only be moving the mike a few inches if at all. The mike was 6" to the left of the trigger with the gun held unnaturally. Holding a gun naturally, my trigger finger is about where my jaw is. Six inches to the left is about where my ear is.

Walter, your mission should you accept...........
Measure  levels of the springers listed when the meter is located next to the shooters gun side ear.  A measurement of the action with respect to the shooter. 
Title: Re: Air Gun Noise Levels
Post by: gandalfretlaw on August 28, 2012, 07:09:56 PM
I find it interesting that for almost all guns the action noise was greater than the muzzle report. The only exception was the Benji 312 pump and the CO2 gun was nearly identical (probably within margin of error).

This should mean that the most significant thing you can do to to quite your gun is tune it or break it in well. The muzzle report probably isn't going to change very much unless your gun starts shooting faster or slower. A different pellet might make a difference though. I'll have to do a pellet test sometime testing various pellets down my Whisper.

The Air Hawks lack of spring noise is interesting. Or perhaps it's the dieseling making the muzzle blast louder. The Benji Trail has a sound like a crack, it's more like a powder gun. There is no springing around at all, just a solid thaWak.
Title: Re: Air Gun Noise Levels
Post by: QVTom on August 28, 2012, 07:17:38 PM
Oops! I didn't see that last column. Darn Andriod browser!

Good data, shows where the noise reduction is needed - the action.

Tom
Title: Re: Air Gun Noise Levels
Post by: Bullit on August 28, 2012, 08:07:10 PM
Yeah Walter, I think that's very representative.  Xlent!
I am looking at your last 3 columns as their the most equal to where measurements would be made by OSHA

Look around inside (if it's not sealed) for a little potentiometer that you may be able to adjust upwards.
Use an electric drill as your base sound and crank it up a little until you get the meter closer.  Might not be possible...just throwin' it out.   
Again....GOOD JOB Bud!!!  Mike
Title: Re: Air Gun Noise Levels
Post by: Bullit on August 28, 2012, 08:14:47 PM
Your Airhawk may be well assembled...lucky you.
The CO2 is inherently more noisy and "sharp", vs equally powered springers.
I hope more folks try to ABSORB the 6"muzzle readings, versus the 6"trigger area readings, before they think they need to modify the muzzle report of their airguns.  I'd almost eliminate the average readings so they concentrate on your readings at those 2 areas, (6" muzzle and 6" trigger).  Mike
Title: Re: Air Gun Noise Levels
Post by: gandalfretlaw on August 28, 2012, 08:58:33 PM
You've got it. A lot of the interesting data is over there at the right.

If you look at the Big Cat and Whisper, both guns are essentially the same, but with the Whisper having the silencer. Doing the math there is a 5.1db difference between the muzzles with the Whisper quieter, hummm, that is significantly quieter, actually on par for about 50% quieter. From my research an increase of 6db doubles the sound pressure. This would mean the baffles are doing their job. Sorry that this comparison actually comes out looking the other way. :-(

Now lets take the perceived noise. The Big Cat is 86.6 and the Whisper 81.8 for a difference of 4.8db again with the Whisper quieter by a significant amount (about 40% quieter). This difference would be mostly from the action being well worn in as it's never been tuned to my knowledge.

Overall noise is Big Cat 83.4 vs Whisper 82.3 or just 1.1db quieter. Compared at ten feet it's Big Cat 76.9 vs Whisper 72.0 for a difference of 4.9 again nearly double the sound pressure. On looking at that perhaps the 1 foot measurements are off for the whisper as it actually got noisier moving away from the gun, hard to say.

Overall the Whisper is nearly half the noise level of the Big Cat, but undoubtedly this would be a lot closer if the Big Cat were tuned or worn in.
Title: Re: Air Gun Noise Levels
Post by: Bullit on August 28, 2012, 09:20:42 PM
IIRC 6dB+ equals 1 S unit.  That's a bunch...when you consider it takes double the power to raise another unit.
Title: Re: Air Gun Noise Levels
Post by: gandalfretlaw on August 28, 2012, 09:45:16 PM
Well yes and no. An air gun isn't exactly a noise generator, so I don't think the +6db means double the power in terms that we're thinking. In our case the noise is a byproduct. In a speaker, yes it would take twice the power, but I don't think that relationship is true of an air gun.

IIRC 6dB+ equals 1 S unit.  That's a bunch...when you consider it takes double the power to raise another unit.
Title: Re: Air Gun Noise Levels
Post by: robert w on August 28, 2012, 09:53:10 PM
interesting we need to smooth our guns out a little , might damage our ears in the long haul. good job walter
Title: Re: Air Gun Noise Levels
Post by: Bullit on August 29, 2012, 09:28:16 AM
 I shoulda said double sound pressure, my mistype...
Sure, the air rifle is a sound generator...just different.
I'm a Ham, so I studied it from antenna gain and pwr transmitters, and it's true, you have to double each dB level to get to the next "S" unit.  I'm sorry I'm not the best at explaining it tho.
Again...your 6" readings are VERY informative.  As well are your readings away from the air rifle.  I'd lose the average column tho, to concentrate on the others.
Thought I'd throw this at you for some comparison to common sound levels in our daily lives - note the level of a "Cap Gun" :D :
http://www.noisehelp.com/noise-level-chart.html (http://www.noisehelp.com/noise-level-chart.html)