They're all useful tools but limited by the SPL handling of the mic. The built in mic starts to become compromised at only 100 dB so above that you'll want to use something more purpose built. I haven't used Decibel specifically but all of the Studio Six Digital stuff I've used has been, again within the built in mics limitations, stupid accurate.
for me it's more to do with making sure i'm monitoring at 85db or so, so that i don't get fatigued or problems with my ears on long sessions!
and also perhaps going outside and seeing how much sound might be leaking etc.
if it's over 100db then i'm already in trouble ;-)
hopefully it's accurate enough... doesn't the mic have a HPF on it though?
A thought occurred to me , I'd bet if you recorded something with your IPhone , you would hear problems and things amiss , those missing things might be a guide to it being unacceptable .
Got to say this is all cr@p from the top of my head , don't even own an IPhone .
Old timer here, new account. Sorry to resurrect an old topic but I was looking for some sound apps for my work (entertainment/sporting events) and I found some relevant information that I think would be very helpful to the forum. There are several articles and studies out there, the most comprehensive is done by scientists at the National Institute of Occupational Safety and Health.
They looked at hundreds of apps, both iOS and Android. Found out that iOS apps SoundMeter by Faber Acoustics and SPLnFFT by Fabien Lefebvre are the most accurate and within 2 decibels of their type 1 sound level meter. Other apps that did well, Noise Hunter by inter.net2day and NoiSee by Noise Lab. Android apps didn't do so well.
There are a couple of other studies where SoundMeter and SPLnFFT show up, one done by Safety Awakenings and one by grad students at a couple of different universities, though none of those studies are peer-reviewed and not as thorough.
Finally, if anyone interested in an app for audio or professional work, get an app that allow you to calibrate to a known source and invest a bit of money in an external mic, there are some really good ones out there.
There are several recent studies, by a govt lab (NIOSH) and universities (University of Florida/Western Ontario) that looked at the accuracy of such apps. Several of them have performed as well as a type 2 SLM. iOS apps outperformed Android apps in the study, search for smartphone sound measurement apps.
What apps? I've been using mine for mixing at appropriate volumes but I always assumed it wasn't terribly accurate.