This time is then multiplied by the appropriate factor to extrapolate to the RT60 value. The noise signal is then turned off, and the system monitors the level, recording the time that the signal is 5dB below the steady state level, and then checking for the signal to reach either 35dB below steady statefor T30, or 25dB below steady state for T20.
#CAR TRUERTA SWEEP OR PINK NOISE GENERATOR#
The interrupted noise method works by first turning on the pink noise generator to "charge" room, allowing the test signal to build up to a steady state level, and then measuring that level in each octave band. The system automatically adjusts the timing of the signal and the pauses between signals to allow a complete test. Set this to a value larger than what you expect for the room, to allow enough decay time for the signal. There is a setting to select the maximum decay for the room. You can set it up to just take single tests, to run and average several tests at one location, or to store and average test data for multiple locations in the room.
![car truerta sweep or pink noise car truerta sweep or pink noise](https://trueaudio.com/images/rta_0404_filter.gif)
Gated Noise RT60 can be customized in several ways.
![car truerta sweep or pink noise car truerta sweep or pink noise](https://pinkfishmedia.net/forum/proxy.php?image=https%3A%2F%2Ffarm8.staticflickr.com%2F7076%2F7113233423_54b91f8458.jpg)
RT60 results appear next to those bands as they are computed. As the tests run, the RTA bars for each octave band are shown in real time. You can turn on RTA bars by tapping the icon on the main screen with the 3 vertical bars. Use the markers and the cursor on the RTA bars to check this when you are running tests. 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. Since it is challenging in the real world to create a test signal that is 60dB above the room abient 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 industry standard metric for room reverb is RT60, which means the amount of time that a sound takes to decay by 60dB.
![car truerta sweep or pink noise car truerta sweep or pink noise](http://www.ymec.com/hp/signal2/images/whiteoctave.gif)
Gated Noise RT60 supports both of these requirements. 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 works well with the internal iOS device microphone, but to meet the standard a Type 1 microphone system is required, such as our iPrecisionMic.