Larson Davis System 824, Reference Manual

Page: 484 / 536

C-16 824 Reference Manual 9/13/00
NOTE: Results in dB referenced to 1013
mB
Position of Instrument and Operator:
When making a measurement, it is recommended that the
observer be positioned as far behind and to the right of the
instrument as possible to minimize interference of the sound
field at the microphone resulting from body reflections.
When using the 824, the meter is held in one hand with the
arm extended away from the body. Better results can be
obtained by using a tripod.
Effect of Windscreen:
The Corrections which should be added to the measured data
when using the Larson-Davis Model WS001 3
½
inch diam-
eter windscreen with a
½
inch Larson-Davis microphone are
as indicated in the following graphs.
Pressure
Response of Free-
Field Microphones
(Variation over Pressure)
Pressure 650 mB 750 mB 850 mB 925 mB 1013 mB 1100 mB
2520 .3831 dB .2049 dB .1371 dB .0688 dB 0.000 -.0462 dB
2540 .3396 dB .2391 dB .1488 dB .0804 dB 0.000 -.0753 dB
2541 .4272 dB .3062 dB .1891 dB .0989 dB 0.000 -.1019 dB