BRUEL & KJAER 2116 Instruction Manual page 31

Audio test station

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Circumaural headphones: use weights to provide the desired force but do not exceed

1 0 N ( 1 kg force).

Connect the signal from the OUTPUT socket on the rear panel of the 211 6 (See pin

diagram Fig. 3

2) to the external excitation source.

Ensure that COMPRESSION switch is in "Out" position, so that a constant voltage

output is obtained, and that the preamplifier is connected to the INPUT.

1 0

Select a suitable output level using the SPL dB UP and DOWN pushkeys

An output

range of 40 dB, from 2,5 to 250 mV (nominal), in 5 dB steps, is available

11. Select the required measurement parameter and press RUN to start the measure-

ment. Its LED will come on, and the one in the pushkey beside it will continue to

flash to indicate that the instrument is operating in the COMPRESSION "Out"

mode, supplying a constant output voltage withtout reference to a stored correction

curve. A typical telephone earphone frequency response to a constant voltage input

is reproduced in Section 1 Fig. 9

5.3. USE WITH THE ARTIFICIAL MASTOID TYPE 4930 FOR MEASUREMENTS ON

BONE CONDUCTORS

The Audio Test Station Type 211 6 can be advantageously used with the Artificial Mas-

toid for frequency response and distortion measurements on bone conductors. The gener-

ator section supplies a suitable test signal to the bone conductor and the analyzer sec-

tion analyses the signal from the force transducer built into the Artificial Mastoid. The

measuring set-up is simple and the measuring process straightforward.

A direct voltage calibration should be used as in Section 4

2 .3

Reference may then be

made to the calibration chart delivered with the Type 4930 Artificial Mastoid. A diagram

of the instrument is shown in Fig

5.4.

Fig. 5. 4.

The Artificial Mastoid Type 4930

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