SCHAAN, Lichtenstein�The XL2 is the new measurement tool for RT60 reverberation from NTi Audio. Designed to measure the time it takes for the sound level in a room to drop to 60 dB after the sound source is removed, the XL2 features two measurement methods that are in line with the current ISO3382 standard.
The two methods employed by the XL2 are the T20 method and the new T30 method. The T20 method measures a drop in sound level of 20 dB, while the T30 measures a 30 dB drop; the measured values are then extrapolated to 60 dB. The T20 is designed for a smaller dynamic range and a lower signal level. The T30 produces a more accurate reverberation time and linear sound decay.
A Schroeder reverse integration method is used by the XL2 to measure the RT60 reverberation spectrum in octave bands from 63 Hz to 8 kHz. The optional �Extended Acoustic Pack� increases the measurement resolution to 1/3 octave bands in the range from 50 Hz to 10 kHz.