Hello everyone,

I'm looking into sound levels for 9mm vs .22LR and can't find any comprehensive guide or graphs that compare all of these dimensions on a similar firearm.
Basically, it's looking like a suppressed 9mm (supersonic) runs about 126 decibels, while a .22LR runs about 116 decibels.
I'm curious what sound pressure level I can expect by running the suppressed 9mm with subsonic ammunition. One would guess it would be between 116 and 126 decibels, but where would it fall?

116 to 126 is a pretty big difference.

Too many variables. That chart is missing ton of info, like different  between subsonic info vs standard velocity etc

Barrel length being one.

Ammo selection (not all created equally)

Suppressor length

Suppressor design

While it would be valuable if someone were to test all of these variables against one another, my post is only looking for suppressed 9mm subsonic vs suppressed .22LR on a similar firearm. Likely the same model of handgun with a conversion kit.

My suppressed G17 with subsonics is still louder than my Ruger .22 MKIII with subsonics.  

Both are fine outdoors without ears on.  The 9mm is NOT with supersonic ammo.

He's right.  There is no way to answer your question, it's too vague.  Do you own a suppressor?  Have any familiarity with them?  I would recommend ignoring the decibel readings.  BTW, that graphic is complete trash, I have several of these guns and it's not accurate.  
What specific platform are you looking at?  A glock 17 isn't a Walther P22.
A suppressed 9mm Glock shooting subs will always be louder than a suppressed .22lr glock shooting subs. How much louder varies wildly on the suppressors and ammo.
Just because a can meters lower at the muzzle doesn't mean it will sound quieter to you.  Some cans get a super quiet muzzle reading by having enormous backpressure, which makes the gun sound much louder to the shooter.

No offense, but having trouble understanding why you guys are bringing more variables into play.
Why would you consider using different barrel lengths?

Thank you for the helpful response.

Very few 9mm silencers can get below 120. Yet almost all decent 22 silencers can get below 115. So I would guess you would be in the low 120s. But if you told us your gun, silencer and ammo, someone might have already tested that combo and you could get a more definitive answer.

That chart is a bunch of BS.

The sonic crack at the end of your barrel from shooting super sonics is enough to cause damage. The suppressor isn't stopping that. Mind you, the AMOUNT of damage is vastly reduced for every decibel you drop, and you probably aren't talking significant damage immediately. Accumulated exposure will cause problems.
140 is the threshold for actual pain. Anything past about 90 you should wear hearing protection if there will be extended or repeated exposure.

People generally under estimate the need for hearing protection. Suppressors help, but other than subsonics they are not negating the need for hearing protection. They just reduce the downside of NOT wearing it.

The reason folks are talking about barrel length is that if you shoot something that doesn't completely burn or barely finished burning by the time it exits the barrel you get a significant flash over when it hits open air. A suppressor helps, but that's why you have the first round pop phenomenon. An 18" barrel 308 is going to be LOUD even suppressed. You'll have a gout of flame coming out past the can and you overwhelmed the can with the gas supply. On the other hand, a 26" barreled model will be much quieter and if you shot subsonics it could approach movie levels of quiet.

They aren't "bringing in more variables", they are trying to explain to you that all those variable already exist and factor into the final numbers and barrel length plays a significantly part. A round that will stay subsonic in a shorter barrel may become supersonic in a longer barrel. So same gun, same ammo will be louder with a longer barrel.


And here's another variable for you. Even if a suppressed 9mm handgun with subsonic ammo was the exact same sound level (and tone - another variable) as a suppressed .22LR handgun, the .22 will still be more enjoyable to shoot. Many people don't enjoy shooting centerfire handguns suppressed because centerfire suppressors add a significant amount weight and length to the end of the gun completely screwing up the balance and handling of the gun. On top of that, recoil will increased and you will have blow back (powder blown back in your face) to deal with.

if you want to shoot a handgun suppressed, .22LR is where its at. if you want to shoot 9mm suppressed, a PCC is where its at.

Disagree.

What can(s) are you running?