In my opinion those apps are toys, I have used one mlyself comparing it to an Cirrus optimus CR160 and they are not accurate. If your considering using this for noise at work or ENV testing - dont even go there. They are not class 1 or 2. Toys only

I have also used such an Ap on my iphone and see it as a useful guide and a starting point for more information. The lads on site seem to think these Aps are brilliant and they believe the readings.

I have one on my phone and so does a colleague. Having done noise monitoring for a council I understand the need for accuracy (especially if considering prosecuting someone!) in respects of noise monitoring and so only use my sound meter app purely as a guide alongside (as another post stated) my hearing. As a quick guide it is really useful and where the level indicates there may be an issue I then go and get our calibrated sound meter to take accurate noise readings. I do not see the harm in them as long as they are not relied on as an accurate assessment of noise levels.