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Optimus+ Sound Level Meters – User Manual
Your Optimus+ GPS sound level meter will automatically make adjustments for the level
produced by the acoustic calibrator and the microphone type fitted to the instrument.
9.2.1 Background noise
In order for the calibrator to operate as intended, the ambient acoustic noise level should be no
greater than 80 dB(A).
9.2.2 Stabilisation
In order for the sound pressure level and frequency to stabilise after switching the calibrator on
when coupled to a microphone, a period of at least three seconds should be allowed before
performing a calibration.
9.3 Changing the battery
The CR:514 and CR:515 acoustic calibrators use a single 9 V alkaline battery. This type of
battery is known as 6F22 or NEDA 1604. It is also commonly known as PP3.
1. Unscrew the screw holding the battery cover on, using a coin or the keyring provided.
2. The battery can now be eased out of its holder and replaced. The battery should be eased out
terminal side first by pushing against the spring at the other end.
Ensure that the battery is inserted with the correct polarity, with the negative terminal in contact
with the larger cut out.
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