Threshold; Threshold / Adjusting The Background Audio Level - Minelab GPX-4000 Quick Start Manual

34

Threshold

Adjusting the Background
Audio Level
Threshold is the constant audible background audio
tone or 'hum' produced by the detector.
The level of the Threshold should be set low, but still
audible and stable. Ideally it should be a smooth,
Threshold
gentle hum.
Small targets or large deep targets may not produce
a distinct target signal, but may cause only a small
variation in the Threshold.
If the Threshold level is set too high or too low, these
very small variations may be missed.
Listening for a target signal with a high Threshold
would be like trying to hear a whisper within a
crowded noisy room. A high Threshold volume may
also be uncomfortable for your hearing.
If the Threshold is set too low, the target signal
needs to be loud enough to become audible,
therefore very soft target signals from small or very
deep targets may not be heard.
It is important to reset the Threshold level as
conditions change. For example, your ears may
adjust to the low levels of audio after an hour or so,
or the conditions may have become windy.
When the Threshold is
too high, a faint signal is
masked, and only the peak
of the loud signal is audible
above the Threshold.
With the Threshold set
correctly, both target
signals are easily heard.
A Threshold level that is too
low does not allow faint
target signals to be heard.
35