The
CAL511 accepted
internationally 1 kHz represents the "0 dB" reference point of
A, B, C Weighting and other filters utilized in acoustic
measurement. The Pistonphone - a mechanical sound source -
offers a slightly higher degree of accuracy at a substantial
increase in cost. In addition, the 200 or 250 Hz operating
frequency is mechanically limited and not suited for
measurements of filtered inputs. The 0.2 dB accuracy is quickly
lost in the 0.7 to 1.5 dB tolerances acceptable for weighting
filters at frequencies around 250 Hz. It's 94 dBSPLdue
totheInternational standards have established 1
Pascal (Pa) as 94 dBSPL. This reference point is now accepted
for specifying the sensitivity of microphones. The uBar found in
some specifications refers to 74 dBSPL (20 dB less than 1 Pa). The
CAL511
calibrator
is easy to use. Attach the microphone to be tested to your
Audio Analyzer (such as a Gold-Line-Europe DSP30) and insert
the microphone into the opening in the calibrator. Press a
switch to activate the Calibrators test signal. The signal is
at a specified level . Your RTA will show the level produced by
your microphone to validate that your microphone and RTA are in
agreement with the calibrator
