Model 737 Soundtrack Loudness Meter - Leq(m)
Operation and Features
2-2
2.1.1
6/4 – 2 Channel Switch
Located to the left of the input trimpots (see Figure 2-2), this switch may be used in
future versions to introduce a fixed offset in the measurement of two-channel encoded
material. Presently (version 1), the offset is set to zero so
the switch has no effect on
the measurement
.
2.1.2
Input Trimpots
To derive accurate and repeatable Leq(m) measurements, the input trimpots are used to
calibrate the Model 737 to standard input levels. The input trimpots are screwdriver-
adjustable and allow sensitivity adjustments from -12 to +4 dBu for Dolby Level to suit
a wide variety of console setup levels and cinema processor types. See Section 2.3 -
for a complete discussion of how to connect and calibrate
the Model 737 to different signal sources.
2.1.3
Trip Set
Trip Set
is a 16-position switch that sets a value from 78 Leq(m) at position
0
to 92 Leq(m)
at position
E
in 1 unit increments. When
Stop
is pressed to end the measurement, if the
Trip Set level has been exceeded, the Trip LED lights and a signal is sent to Trip Out.
The Trip LED does not light during the measurement to allow transient Leq(m) values
to exceed the Trip Set value without triggering Trip Out.
Note:
The Trip circuit can be disabled by setting the switch to position F.
The current Trip level can be checked by holding down the
Cal
button then pressing
and holding the
Stop
button. This test always sends a signal to
Trip Out
to check the
circuit operation. Push the
Run
button to cancel the trip indication. In position
F
, the
display is blank.
2.1.4
Pushbuttons
•
Cal
– Push to enter calibration mode to set audio input levels using the trim-
pots. In calibration mode, Mon Out sends a mono mix of the channels instead
of the output of the filter. Push Start to return to measurement mode.
•
Start
– Push to begin a measurement.
•
Stop
– Push to stop a measurement and display the final level of the measurement.
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