Manual

39
To enter the 1/3
rd
OCTAVE SPL mode (Fig 3.20), select 1/3
rd
OCT. ->
SPL in the measurement functions submenu.
Arrow Readout: The arrow readout displays the frequency and
the level of the 1/3
rd
octave band that it points to. The arrow
automatically points to the highest level in the 1/3
rd
octave spectrum,
or, alternatively may be controlled manually.
Arrow Mode: The arrow readout may be moved manually to a certain
specic 1/3
rd
octave band.
• Select the arrow mode eld and press the enter key.
• Move the arrow to any frequency by using the left/right keys.
Run/Pause: The 1/3
rd
octave spectrum may be freezed.
• Select the run/pause eld and press the enter key.
• The1/3
rd
octave spectrum is freezed.
• The arrow mode or zoom symbol may be selected for the detailed
read out of the 1/3
rd
octave spectrum.
• At selecting any other eld the measurement will be continued.
• Press the enter key again to continue the measurement.
Zoom(Y-Axis): The scaling of the spectrum’s Y-axis (sensitivity) is
xed and may be adjusted manually.
• Select the zoom (Y-axis) eld and press the enter key.
• Use the up/down keys to scroll the displayed level along the Y-
axis and the left/right keys zoom out/in the Y-axis, e.g. alter the
resolution of the division.
Time Constant: The time constant corresponds to the integration time
of the 1/3
rd
octave recording. It may be set to ve value: 0.2 / 0.5 /
1.0 / 2.0 / 5.0 seconds. A lower time constant results in a quicker,
more ‘nervous' display, whilst a higher time constant ‘averages’
more samples, thus providing a more stable spectrum.
Bargraph: Below the spectrum, the actual sound pressure level is
indicated by a bargraph. Select the different indication ranges by
moving the cursor to the left or right arrow below RNGE and press
enter. The available bargraph ranges are:
• 20 - 100 dB
SPL
• 40 - 120 dB
SPL
• 60 - 140 dB
SPL
Measurement Functions