Suppressor Testing??

[mudslinger021485]

Appreciate the tests and data. Thanks for doing this. Ryan, your humility shows. Thanks again

THIS

 

[Ucsdryder]

@Ryan Avery any thoughts on felt recoil, tone, shootability? It didn’t look like your test was quite set up for those questions, but I’m curious if you noticed anything different between the 4 cans regarding shootability.

 

[4th_point]

I don’t know how it works. I haven’t used, or been around the non professional level systems really until a year or two ago.

FYI - If you have a Class 1 sound level meter (SLM), it's still precision grade. Just may not have high sampling rate like a high end DAQ/analyzer. Class 2 meters have lower criteria for specs and are less expensive. Both are useful tools, but the operator needs to know when they are appropriate to use.

But, it is VERY obvious with all bystanders that randomly a known, extremely consistent can meters 136-137 dB- that there is no way is real, given that same shot sounds to everyone exactly the same as the ones metering 129 dB.
For instance, it is not unusual to have the TBAC UL7 Gen 2 to randomly pop a 135-137 dB(A) on a 20” 223. That isn’t real. Not at all. That never shows up in real systems. Not only that- frequently two, calibrated identical Spartan meters don’t read the same when it happens.

Any chance you are catching the sonic crack, or have some reflective surfaces nearby?

Regarding the two Spartan units, double check the model numbers on the microphone cartridge, which is the open end of the mic with grill, and the preamp which is the rest of it or body. It may look like a single unit but should be the mic and preamp. They should unscrew but check the manual in case they are sealed or a single unit.

Do these model numbers match for both meters?

Be very careful doing this, but you can inspect the diaphragm for damage. It should look like metal foil under the grill. That's what detects pressure. It's really just a pressure gauge. I've seen these get damaged but usually it's more severe than what you described, but probably still worth checking. Don't drop anything though! I've seen diaphragms get damaged from fiddling.

I'd also compare meter settings, side by side, to make sure something didn't get changed. It can be a little confusing, especially if the menu layout is poor.

I’m saying that absolutely cans meter different in different conditions. And it is frequently a 3-4 dB range up and down.
I am not saying it is a huge difference when metering with correct systems; I am saying that it is with the meters that almost everyone is using.

What is the calibration status of these meters and mics?

I am stupid on this; are you saying environmental conditions don’t cause variability in testing suppressors?

The ambient temperature can obviously affect combustion and pressure. Have you been keeping track of velocities too?

Sure. Recall what I actually wrote- we can quote it if you want in its entirety in case I am mistaken. IIRC- what I stated was that A weighting is what the entire industry uses, and not being a professional sound person- that from what I have been told, it is fine for this use because we don’t actually know what is “safe” and “not safe”- the unknown is so large that as long as you are comfortably under 140, it’s probably about as fine as you will get. Also remember, that I started showing the Z-weighting afterwards.

You disagree with that- awesome. Can you tell me how and why, and how I can functionally use that information? How do I compare one can that only has A-weighting listed, with another can that uses Z-weighting?

Not any of that has to do with whether the meters being used are accurate enough to pick up the difference in 1-2 dB.

FFS you have people on here claiming that cans are metering in the 120’s on right side ear from an AR15…. And everything is good because “that’s what the meter says”.

100%. I am ignorant as can be. Can you or omicron educate and teach me where and how 2dB difference (129 to 131 say) is changing how I use a can, or what steps I must take to remove the risk increase?

If you record unweighted sound files, you can post process with whatever filter you want like A-weighting.

If people are using insufficient sample rate, or wrong mic, or bad settings, they probably won't catch the pinnacle of the waveform.