Larson Davis System 824, Руководство по обучению

Страница: 58 / 66

3-6 824 Training Manual 3/22/01
You can trigger your pink noise ON
& OFF manually though you may
find pulses of noise more convenient.
Step 4
You will need to configure your generator (Larson
Davis SRC20) to output pink noise in pulse mode
with an ON time of 2 seconds and an OFF time of
5 seconds. Unmute the generator to drive the
amplifier for a test run to check your levels in the
room. Adjust levels on the amplifier if necessary.
Step 5
If the levels are within 80 to 100 dB you are now
ready to take a measurement. Press the VIEW
key, highlight “Trigger” and press the right arrow
key. Select “Status” and press the Check
key.
The “Trigger Status” display will show these four states
sequentially as the measurement is taken:
• Stop
• Ready
• Armed
• Triggered
NOTE: Triggering is performed on
one frequency band (or Flat) as
selected by the “Trigger Source”
setting. If desired you may change
this to a band that has the energy
profile that will be best to trigger
from.
Step 6
Press the RUN/STOP key on the 824 to put the
824 in the “Ready” mode. Start the generator to
energize the room with noise. As the noise pulses
ON and reaches a level > 80 dB the 824 will
change to the “Armed Mode”. When the generator
pulses OFF and drops below 80 dB the 824 will
change to the trigger mode and start recording an
autostore. After 3 seconds the autostore will end
and the 824 will stop.
You now have an autostore record in memory from which
the RT60 can be calculated.
Trigger Status