Gated Noise RT60 works well with the internal iOS device microphone, but to meet the standard a type 1 microphone system is required, such as our iPrecisionMic. The standard suggests doing several tests at different locations in the room, and for each location, averaging several runs of the test. Gated Noise RT60 supports both of these requirements. The industry standard metric for room reverb is RT60, which means the amount of time that a sound takes to decay by 60dB. Since it is challenging in the real world to create a test signal that is 60dB above the room ambient noise level, the T30 and T20 calculations are used, where a noise signal that decays 30dB or 20dB is used to compute the 60dB decay time. The standard requires that the test signal noise to be 45dB above the ambient noise floor in the room for T30, and 35dB above the noise floor in the room for T20, for each octave band. Use the markers and the cursor on the RTA bars to check this when you are running tests.