NTi Audio XL2 Sound Level Meter - Manual (Page 81)

81
Reverberation Time RT60
RT60 Measurement - Getting Started
Test Signal: Pink Noise
Play a pink noise signal through an omni-directional speaker in
the room under test. The sound source should be played for
a long enough time period to ensure that a balance between
injected and absorbed acoustic energy has been reached. For
example the sound reflections should be given enough time
to reach all reflective surfaces in the room. As a rule of thumb,
ensure that the pink noise is played for at least the time period
of the estimated RT60 test result. If in doubt, play the Minirator
MR-PRO or the Test Signal CD as sound source for at least 5
seconds for each cycle. Each time the source signal stops, the
XL2 recognizes this interruption, triggers, measures the decay
time and calculates the reverberation time automatically.
Test Signal: Impulse
Fire an impulse sound source in the room under test, e.g. use a
starter pistol. The XL2 measures the decay time and calculates
the reverberation time automatically. Do not fire the next shot
until the previous calculation is complete i.e. until the status
4
displays ARMED.
Test Preparations
The XL2 reads the electronic data sheet of any connected
ASD microphones provided by NTi Audio and switches the 48V
phantom power automatically on as follows:
Connect the measurement microphone to the XL2. •
Switch on the XL2 • .

The 48V phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.
Position the XL2 at the measurement location using a micro- •
phone stand or tripod.
Select the
• RT60 function in the measurement menu and
toggle with page to the run page RUN.
Prepare the environment for the measurement. For example •
mute all sound sources to establish silence.