Larson Davis System 824, Руководство по обучению

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3/22/01 RT60 Measurements 3-5
See the 824 Reference Manual,
chapter 10, for details concerning
each of the setup parameters. Since the RT60-A setup is already configured to take a mea-
surement using steady state noise, let’s setup our generator
and speaker to energize a room with noise.
Step 3
Just to get a feel for an RT60 measurement, con-
figure your speaker, and 824 as shown above.
Hint:
Before making an RT60 measurement keep the following in mind:
• The background noise in the room should be kept to a
minimum. If possible turn off any noise makers such as
HVAC systems. Shut all windows and doors and do it
during an appropriate time of day when your test will be
free of interference.
Caution: Wear hearing protection
when generating noise levels of 90
dB or more. Remember that levels
will be greater near the noise source. • Make sure you can energize the room with enough noise
to get a valid measurement. 100 dB would be an ideal
level but is not always achievable. Shoot for a level
between 60 to 80 dB.
• It is preferable to use an omni-directional speaker to get
uniform coverage in the room. If you have to use a single
speaker, direct its energy into a corner to obtain better
results.
WARNING!
Be careful when driving your loudspeaker as pink noise has
equal energy per octave. Over driving them may cause fail-
ure. This is especially true for high frequency transducers
(tweeters) which may have reduced power handling capabil-
ities.
Place your 824
on a tripod out
of the near field
of the noise source