Gain / Adjusting The Sensitivity Of The Detector - Minelab GPX-4000 Quick Start Manual

64 Audio Type
Changing the Audio
Response of Target Signals
Range
Factory Preset
The Audio Type function replaces the Boost switch
on the previous GP Series detectors. There are four
options to choose from. Each setting changes the
way that the detector interprets a signal and how
that signal is produced as an audio response.
Normal
This may be used for general detecting conditions.
Normal provides the best compromise for signal
response and Threshold stability.
Quiet
This gives the most reduction of both ground noises
and interference. The signal response is slightly
quieter compared to the other Audio Types, so
should only be used in the most extreme situations.
Boost
This is a more aggressive Audio Type. Boost will
provide very sharp target signals but will also
increase any signal caused by ground noises or
electrical interference. It is best used in milder soils
and well away from electrical interference.
Deep
This is the preferred Audio Type when searching for
larger targets at depth. It works well in combination
with the slower Motion options, where target signals
come through loud and clear, but noises from
ground and mineralisation are somewhat filtered
out.
Note: Each Audio Type will have a different optimum
Gain setting you should check the level of Gain if you
make changes to Audio Type.
Normal, Quiet, Boost, Deep
Patch Boost General Normal Deep Deep
Gain
Adjusting the Sensitivity
of the Detector
Range
Factory Preset
The Gain function allows the GPX-4000 to be
optimised for differing conditions, controlling the
sensitivity of the detector to its environment and to
targets.
The detector, with a high Gain setting, will detect
smaller and deeper targets but may respond to
unwanted noise and ground signals. A high Gain
setting is recommended for mild soil conditions and
areas of low interference.
The detector, with a low Gain setting, will detect less
unwanted noise and ground signals, but may miss
deep targets. A lower Gain setting is preferable for
variable 'noisy' conditions or high interference areas.
The Gain control should be adjusted to suit the soil
conditions, as well as the coil being used. E.g. if you
have found some nuggets in an area and wish to
detect the same spot with a larger Monoloop coil, it
may be necessary to reduce the Gain setting.
Always ensure that you are properly Ground
Balanced and that the detector is tuned before
making any changes to the Gain setting.
Note: Try using a slower Motion setting (pg. 66) and/or
the Coil/Rx switch in Cancel (pg. 44) to allow a higher
Gain setting.
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Patch 7 General 8 Deep 9