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PostPosted: Sun Mar 12, 2017 6:25 pm 
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Got a rugged oculus in and wanted to compare with the dead air mask.

Did some meter testing of the two, cold day here 30* no wind.
Used Larson Davis lxt1-qpr and tested 1 meter left of bore.

Host was Ruger 22/45 lite, ammo was American eagle 45 grain subsonic.

Base line without silencer 2 shots 157.5 & 157.5

The results are 10 shot averages:

Rugged Oculus Avg. 118.42 db Weight: 7 oz. Length: 5.25"

Dead Air Mash Avg. 122.01 db Weight: 6.8 oz. Length: 5.125"


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PostPosted: Sun Mar 12, 2017 8:36 pm 
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Nice work. Got any vids? And to your ears, we're the 4 dB noticeable?

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PostPosted: Sun Mar 12, 2017 11:58 pm 
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I'm a bit surprised by that 122dB result. Todd Magee of Dead Air reported this:
DeadAir wrote:
Sound testing on pistols is comfortably in the 114-116 dB range with minimal FRP.

That is from this thread:
viewtopic.php?t=133188
Later in the thread Hansohn Brothers reported 115.7dB but that was with CCI Quiet, so doesn't really count as that ammunition is very quiet already, certainly worlds apart from American Eagle subsonic loads used in your testing. But NFA Review Channel also put it at under 116dB with subsonics from a 4" pistol barrel. A 6dB to 7dB jump to 122dB seems a bit extreme. Makes me wonder how much value any of these tests actually has in absolute terms... perhaps only useful to do direct comparisons in identical circumstances as you have in comparing to one other can.

The above numbers rather reinforce what I've felt regarding use of a cheap SPL meter for comparisons in-house. While useless for comparing directly to an industry standard meter and microphone with proper calibration and placement in an ideal standardised environment, a very economical Chinese meter has consistently recorded values for various devices I've tested. Numerical values recorded change in different environments, such as in a small room, compared to a large room, then compared to outdoors (lower numbers with each in that order), but remain constant within less than 2dB for a given combination of weapon, ammunition and baffle array in each of these environments. Obviously a $5,000+ sound metering apparatus is impractical for home testing. But from the few comparisons of wildly differing results above, it seems obvious that one needs to consider even those very expensively harvested numbers with some suspicion. Not meaning anything harsh by this towards anyone in this forum or in the industry, only an observation regarding a subject where there has been considerable debate and at times even hostility towards those who dare post comparisons using such low cost devices. My own experience has shown that my ear is always in agreement with the metered results I get from the budget device - improvements in efficiency of a suppressor using changes in baffle design prove quieter to my ears while providing lower numbers with the meter.


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PostPosted: Mon Mar 20, 2017 12:43 am 
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For my purposes, I will sometimes use a cheaper dB meter to sort of "confirm" what I am hearing. I don't put it up against any stated numbers but for side by side comparisons it can offer at least some insight.

i.e. metering 120 on can A vs 125 on Can B, when can A reads 120.5, 119.9, 119.7, 120.1, 118.9 and can B does 125.5, 124.9, 124.7, 125.0, 124.9 within 5 minutes of each other. Are those numbers really 116 and 121 because the cheap device is off on calibration by a few dB? Maybe but as long as it's consistently off you can say "Yeah, can A did seem noticeably quiet, it wasn't just the tone or my imagination...."

In any case, it's why I don't ever talk about my el cheapo Chinese job... out side of a situation like this anyway. It opens way to many cans of worms and trying to go down all those rabbit holes can be exhausting and get some folks riled up. I'm not an expert not a scientific facility so I'm not going to try to pretend I'm something I'm not.

OP- thank you for the numbers, I've heard a few folks say they feel like the Oculus is a little quieter.


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PostPosted: Wed Mar 22, 2017 7:52 pm 
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If your looking for a great read about meters and specifically the meter I used read this link. This was done by Dr. Phil Dater whom I consider to be one of the foremost experts on suppressors and sound testing. This is a great arrival.

http://www.larsondavis.com/ContentStore ... iefing.pdf


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PostPosted: Thu Jul 13, 2017 10:50 pm 
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Are you using Z weighting? Those numbers should be lower. I have the same meter, I haven't metered those cans but my best can meters around 113db with CCI SV. Sico Spectre 2 meters 113-115 as well. Everyone has such great things to say about the mask, I find it surprising it's over 120db, I need to find a local with one to try out.


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PostPosted: Thu Jul 13, 2017 11:02 pm 
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JFettig wrote:
Are you using Z weighting? ...

Recommend A weighting? I think OSHA leans toward C.

I think if things are measured dBA OSHA recommends an adjustment to compensate for the lower numbers dBA will produce.

I think dBC is taken at face value when comparing to NRR.

ETA: OSHA

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PostPosted: Sat Jul 22, 2017 2:48 pm 
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I only recommend A weighting because it's what the industry uses. Z weighting I believe is what tells the most truth.

It's still really difficult to compare apples to apples regardless since every manufacturer has their own guns and ammo they run, but A to A get's you a little closer.


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PostPosted: Sat Jul 22, 2017 4:08 pm 
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Yeah, I see A weighting as the most candy coated, marketing friendly mode that makes everybody's numbers look better.

I would lean toward C weighting if I had a choice because it provides a method of direct comparison to NRR (according to OSHA) which is more or less the standard for hearing protection. OSHA considers A weighting to have an inherent error of 7dB.

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PostPosted: Sun Jul 23, 2017 2:21 am 
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I use C weighting as Dr. Dater recommends.


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PostPosted: Mon Aug 21, 2017 8:39 am 
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I'm quite surprised by this. My masks seem stupid quiet.


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PostPosted: Thu Apr 19, 2018 5:47 pm 
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Deserteaglexxx wrote:
Got a rugged oculus in and wanted to compare with the dead air mask.

Did some meter testing of the two, cold day here 30* no wind.
Used Larson Davis lxt1-qpr and tested 1 meter left of bore.

Host was Ruger 22/45 lite, ammo was American eagle 45 grain subsonic.

Base line without silencer 2 shots 157.5 & 157.5

The results are 10 shot averages:

Rugged Oculus Avg. 118.42 db Weight: 7 oz. Length: 5.25"

Dead Air Mash Avg. 122.01 db Weight: 6.8 oz. Length: 5.125"


Interesting! To my ears shooting a Walther PPQ M2 .22 with the Oculus or the Mask they both seem to come in at about bolt noise but I don't have a meter. The Dead air seems quieter when I'm at the range but our range is a series of pits that cause extra noise from echo. Need to drive up the highway and find a flat area...

George


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PostPosted: Sat Apr 21, 2018 2:39 pm 
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westtxrocket wrote:
I'm quite surprised by this. My masks seem stupid quiet.


Agreed... the quietest can to my calibrated ears and those of my my friends standing 10 yards to my left or right, that is my scientific "G" scale (George)
The Masks are so quiet and have the most pleasant tone....


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PostPosted: Thu Aug 23, 2018 5:21 pm 
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Joe Blk wrote:
For my purposes, I will sometimes use a cheaper dB meter to sort of "confirm" what I am hearing. I don't put it up against any stated numbers but for side by side comparisons it can offer at least some insight.

i.e. metering 120 on can A vs 125 on Can B, when can A reads 120.5, 119.9, 119.7, 120.1, 118.9 and can B does 125.5, 124.9, 124.7, 125.0, 124.9 within 5 minutes of each other. Are those numbers really 116 and 121 because the cheap device is off on calibration by a few dB? Maybe but as long as it's consistently off you can say "Yeah, can A did seem noticeably quiet, it wasn't just the tone or my imagination...."

In any case, it's why I don't ever talk about my el cheapo Chinese job... out side of a situation like this anyway. It opens way to many cans of worms and trying to go down all those rabbit holes can be exhausting and get some folks riled up. I'm not an expert not a scientific facility so I'm not going to try to pretend I'm something I'm not.

OP- thank you for the numbers, I've heard a few folks say they feel like the Oculus is a little quieter.


I like your rant... I've looked at a lot of metered numbers and watched videos with hideous sound compression and clipping and truly believe the best instrument to measure suppressors is that of you and your friends ears. Shooting not under a roof at a range and not in a pit but preferably up on some flat ground not next to other buildings or trees. I enjoy letting my friends shoot my suppressors while I stand and different distances inline and behind the ejection port. Sometimes I will even stand 30 or so yards downrange and about 15 to 20 yards away from where my trusted non drinking friends will shoot at a non frangible target.

The Occulus is pretty damn quiet but so is the Mask. "They" say that it has to be 3-5 dB more or less than the other can for us to hear any difference. The state of 22 suppressors seems to now be where if you are a few feet away all you can hear is the clack of a Ruger 22/45 Lite, a Walther PPQ M2 .22, a Ruger SR-22, Walther threaded barrel .22's before the PPQ.... etc, etc... I like S&B subsonic or Aquila. Gemtech subs are noisy and I don't like American Eagle anything... their 124 and 147 subs may be subsonic but the noise they make in my suppressed 9mm handguns and MP5 is unacceptable. S&B 158, IMI 158 and PPU 158's are all very quiet and to me are just a hair louder than the excellent but expensive and hard to find in Alaska HUSH. My hand-loads are the best at being quiet and functioning everything....

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PostPosted: Fri Aug 24, 2018 9:46 pm 
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Deserteaglexxx wrote:
I use C weighting as Dr. Dater recommends.


C weighting for reality, A weighting for Mil Spec and marketing comparisons. I think you pretty much have to quote A numbers or long threads ensure :D


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PostPosted: Sat Aug 25, 2018 3:19 am 
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Stan1 wrote:
Deserteaglexxx wrote:
I use C weighting as Dr. Dater recommends.


C weighting for reality, A weighting for Mil Spec and marketing comparisons. I think you pretty much have to quote A numbers or long threads ensure :D


Hard to disagree with Doc Dater... I talked to him last year about the Mist barrels... I talked to him in the early '80's about wipes and he was very patient and helpful and seemed excited to talk about his creations!

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