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LARSON DAVIS - Calibrators
Model CAL150
The Larson Davis Model CAL150 is a precise microphone calibrator intended for the 3/8" diameter microphones typically used on the, SoundTrack Lxt class 2, Model 700, 710, 712, and 720 SLM/Dosimeters and the Model 705 Noise Badge. The CAL150 provides a choice of calibration sound pressure levels, 94.0 and 114.0 dB (switch selectable) at a frequency of 1 kHz. The optional adaptor ADP024 is available to permit reference measurements of the CAL150 to be made using the Larson Davis Models 2520 1/4" condenser microphones.
Model CAL200
The Larson Davis Model CAL200 is a Class 1 microphone calibrator intended for the Larson Davis 1/2" or 1/4" diameter microphones. The CAL200 provides a choice of calibration sound pressure levels, 94.0 and 114.0 dB (switch selectable) at a frequency of 1 kHz.
Model CAL250
The Larson Davis Model CAL250 is an ultra precise microphone calibrator delivering a full 114.0 dB level output signal. Its accuracy has been verified against the reference issued by the National Institute of Standards and Technology (formerly National Bureau of Standards).
Outstanding Features
Special adapters make possible the use of 1/4 and 3/8 inch microphones.
Automatic compensation sensors provide accurate calibrations in extreme environments:
Noisy industrial environments (95 dBA)
Temperature changes of 0 to 50 C (32 to 122 F)
Barometric pressure changes of 400 to 1100 mbar
An effective volume of > 100 cm2 (6 in2 ensures
an accurate calibration, even if the microphone and microphone adapter are not fully seated.
An accurate tone is maintained even with a weakened battery.
Model CAL291
Under IEC and ANSI standards, a sound intensity measuring system consists of a two microphone sound intensity probe and a dual channel processor. The accuracy of the intensity measurement is strongly dependent upon the phase accuracy between the two measurement channels, including the microphones. Sound intensity measurement systems are classified into Class 1 or 2 based upon the pressure-residual-intensity index which is measured using a residual intensity testing device. For direct calibration or verification of the accuracy of a sound intensity measurement system, IEC 1043 and ANSI S1.9 call for the use of a sound intensity calibrator which delivers to the probe microphones the simulated intensity at a specified temperature, atmospheric pressure and nominal microphone separation.
The Larson Davis Model CAL291 Residual Intensity Calibrator satisfies the residual intensity test device specifications of both IEC 1043:1993 and ANSI S1.9-1996..
Application
Testing of sound intensity measurement systems
Generation of signals for verification of the amplitude/phase accuracy of multi-channel acoustic measurement systems
Amplitude/Phase Normalization. The digital filters of the Larson Davis 3000+ analyzer provide both amplitude and phase, permitting the measurement of the complex transfer function between two measurement channels, including microphones, in 1/3 octave bands by using the CAL291 to excite both microphones with broadband noise. From this a correction function can be generated within the analyzer to correct for any amplitude and phase errors which may have existed between channels previous to the normalization procedure.
Features
Applies the same signal with zero phase difference to a pair of 1/2" or 1/4" microphones
Driven by external signal generators such as the following versions available with the Larson Davis Models 2800/2900 and 3200 Real-time Analyzers:
OPT 10 Noise Generator; pink or white broadband noise
OPT 11 Digital Signal Generator; Sinusoidal, pink or white broadband noise, 1/3 octave bandlimited pink pseudo random noise and white pseudo random noise
Amplifier provides signal levels to 127 dB
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