Amazing
I have recently had the opportunity to compare with a very calibrated instrument and was very favorably impressed. This thing works very well.
I also checked my Radio Shack meter at the same time and its good right around 1KHz which is where -- if you read its instructions -- it is calibrated. The Radio Shack SPL meter, by the way, while a bargain for the price and quite good for what it is, is not a good tool for tuning subwoofers at all. This iPhone ap, while better, still isnt the best for subs either with the built-in mic, but worked much better with an external.
Also, this aps A-weight filter is better than Radio Shacks.
In conclusion, this ap is a bargain for the price and so handy to have with you.
A+.
My one suggested improvement: a logging mode which logs SPL at selectable intervals -- minutes and seconds -- and then can e-mail the log out in csv format with time and SPL reading.
Gollnick about
SPL