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7.4.5 Indicator (---)
If the --- indicator appears after finishing a measurement, can be because:
•
The sound pressure level reached over the background noise is not enough to calculate
the parameter (T
20
Î
∆
>35 dB and T
30
Î
∆
>45).
•
The reverberation time cannot be calculated.
7.5 Measuring the Reverberation Time by one third octave bands
7.5.1 Measuring the Reverberation Time
The REVERVERATION TIME 1/1 mode of the
SC310
measures simultaneously the
reverberation time (T
20
and T
30
) for one third octave bands (de 50 Hz a 5 kHz) through the
interrupted noise method.
This method lies in obtaining the sound pressure level decay according to time inside the
room that it is being studied. This decay is obtained exciting the room with random noise of
broadband or of limited bandwidth and recording the decay level of the sound pressure when
making a sudden interruption of the noise emission.
To do this measurement, you will need an omni directional sound pressure source (FPA-120)
to emit a broadband noise (pink noise).
From among the applications of this mode you should point up the measurement of the
reverberation time in rooms, the measurement of the absorption coefficient in reverberant
rooms, the measurement of the acoustic insulation in buildings and of building elements.
7.5.2 Visualizing the third octave bands
The SC310 shows the measured data for all the third octave bands in three different sections
(50 – 200 Hz), (250 Hz – 1 kHz) and (1,25 kHz – 5 kHz) to accede to its visualization press
and
. Each section can be change even when there is no measure in progress
( ) both there is a measure in progress ( ).
