Instruction manual

Preparations

Acoustic calibration with pistonphone

For acoustic calibration, the Rion pistonphone NC-72 (option) is mounted to the micro-

phone of the sound level meter, and adjustment is performed so that the reading of the

meter is equal to the sound pressure level inside the coupler.

Important

Be very careful when inserting and removing the micro-

phone to and from the coupler, to avoid a sudden pressure

buildup which could destroy the membrane of the micro-

phone.

1. Turn off the pistonphone.

2. Turn on the NA-27.

3. Press the SLM / 1/1 / 1/3 key to call up the sound pressure level measurement

screen.

4. Use the FREQ/WGHT key to set frequency weighting to "C" (indication "L

" ap-

pears on the display).

5. Use the TIME CONST key to set the time constant to "FAST".

6. Use the LEVEL UP/DOWN keys to set the level range to "120".