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3.3.2 Setting the gain
The amplification of the microphone signal, or gain, adjusts
the level of sound passed from the microphone to the
receiver for processing. A high gain setting would allow the
equipment to detect and process far-off and/or low-level
sounds more easily; close proximity to a leak or loud leak
Fig 10 : Soft Keys for Gain Adjustment
sounds would not require as much amplification and therefore
allow the operator to use a lower gain setting.
Actual pinpointing of a leak s location involves measuring the leak
sound level at a number of different points along the line and then
comparing the measurements to one another to determine the point at
which the leak sounds are loudest. Although a high microphone gain
setting (7-8) is desirable when initially surveying for leak sounds, a
medium gain setting (3-5) is recommended when comparing actual
leak sound levels at different points along the line.
Note: Adjusting the gain (done by using the two soft keys
found on the bottom right of the front panel - see Fig. 10) will
affect both the displayed sound levels and headphone
volume. The bar over the top of the two buttons (Fig. 10) shows
the gain setting on a scale from 1 (min) to 8 (max).
