HBK 4231, User Manual

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+20 dB Level Step
2 Sound Calibrator Type 4231
User Manual
When you want the calibrator to keep working, even when there is no
microphone or coupler fitted, you can defeat the automatic switch-off
function by putting the calibrator on a flat surface (such as a table) with
the opening facing downwards. This is useful if you are calibrating
several microphones one after the other.
✐
Please note:
• If you are using a special adaptor or an adaptor smaller than 1/2

, the
calibrator may not switch off automatically, even when there is no
microphone fitted. Switch it off by pressing the On/Off button.
• If the calibrator cannot maintain the specified sound pressure level, for
example because of a leakage at the adaptor, it will switch off
automatically.
• If the battery level is low, the calibrator will switch off when the button
is released. It may be forced to operate by holding down the On/Off
button as long as the calibrator is able to maintain the specified sound
pressure.
1.3 +20 dB Level Step
The button (see Fig.1.1) increases the sound pressure level by 20 dB
(to 114 dB). Using this button, you can calibrate in noisy environments
and check linearity.
If the calibrator is already switched on when you press the
level step
button, the 114 dB sound pressure level is only produced as long as
you hold the button down.
To start the calibrator so that it works at the higher level all the time,
press the button and within 5 seconds press and hold down the
button until the 114 dB diode lights. The calibrator will now work at the
114 dB level until it is switched off.
✐
Please note:
With some special microphones and ear simulators, the
calibrator cannot maintain the 114 dB level, and will switch
off automatically.