Measuring Sound with your Smartphone - Good Idea or Not?

[pheelgood]

*Moderator, please move if in the wrong place*

Was doing some testing on sounds(loudness) of my airguns for an upcoming review. Based on what I read on some of the forums I had concerns on the accuracy of what I was attempting. I found this article that goes into some detail on the topic. It's dated 2013 so I would expect the results to be similar or better as of 2016.
http://blogs.cdc.gov/niosh-science-blog/2014/04/09/sound-apps/

Synopsis
Most measure within + or - 2 Decibels in most cases
iPhone has better sound equipment in general and provides a consistent result due to only one hardware manufacturer.
External mics can perform better.

 

[NeilClague]

I do not think phones are very good for measuring the DB's of air guns, to measure the report accurately the equipment needs to have a very fast response time, most phones are not designed specifically for this purpose and will not be accurate. I have tried several less expensive DB meters and compared to the more expensive one I purchased their readings were totally unreliable and way off the mark. I doubt very much that a phone will be accurate, but it will at least give you some kind of comparison if you are comparing one gun to another using the same phone and software, Neil.

 

[pheelgood]

Just when I thought I could save a few bucks.... 

 

[NeilClague]

Hey if you just want to compare different guns you own then the phone will most likely be OK for comparisons, but have you seen all of the DB readings people have posted on the forums using phones. I saw one guy post one where he said his DB reading was below 60dbs. Now as a maker of fairly effective LDC 's and shrouds that is a number I would love to obtain. When you think the Marauder .22 caliber is about 85 db's and that is known to be a quiet air gun, that shows just how quiet a sub 60db gun is going to be. With my TV on very low volume, so low I can not hear what is being said I get a background reading in the mid 60's, outside in our field with no real noise I get a mid 50's reading so a sub 60 reading is an amazing achievement, the lowest I have managed to record is 66dbs on a Hatsan 22 caliber, but that took a huge amount of work and not something I can do on every gun, the cost would be prohibitive. I recently turned down a build for someone who wanted his gun dead silent and the customer told me he wanted it to be under 60dbs, Maybe if he was using a phone app I could have achieved it for him? 
Anyway there are some DB meters out there that are more accurate and do not cost you an arm and a leg, but expect to pay a a couple of hundred bucks for anything decent, and that is by far one of the less expensive ones, you could easily drop a couple of thousand on an industrial quality one, Neil.

 

[Paulcat]

I agree with Neil.If what you want to do is compare gun to gun with some figures use the phone app. I have reasonable dB meter I purchased after being diagnosed with above average hearing loss for my age.A quiet room with some outside noise can read about 40 dB.Normal conversation(Which causes me issues) is about 45-55dB.
Also consider the way dB readings work.It is like a parabolic curve when graphed,100dB is not twice as loud as 50 dB,but more than double so gauging some noise by 'ear' will make you think that one gun is way louder than the other,even though the numbers will tell you different.