Decibel Meter Pro 2.0.4
Unless you have access to a calibrated decibel meter, you shouldn’t consider the readings from Decibel Meter Pro to be gospel. Still, this tool will give you an idea of just how loud your servers are. I find it handy to measure how loud a new server is compared to my existing units.
Price: 99 cents
Developer: Performance Audio
Compatibility: iPhone and iPad; iOS 4.0 or later