Minelab 4901 - 0059 Metal Detector User Manual


 
36
37
ADJUSTING THRESHOLD
Threshold is the constant background
sound produced by the detector to help
distinguish between desirable and
undesirable targets.
When a rejected target is detected, the
Threshold sound ‘blanks’ (becomes
silent) to indicate that a rejected target
is underneath the coil.
Speaker/Headphone Threshold
The X-Terra 70 is able to save separate
settings for both the speaker Threshold
and headphones Threshold, switching
from one to the other automatically
as the headphones are connected
(Accessories, pg. 50).
When the headphones are unplugged,
all changes to the Threshold setting are
applied to the speaker Threshold. When
the headphones are plugged in, the
headphones icon will be displayed and
all changes to the Threshold setting are
applied to the headphones Threshold.
THRESHOLD
If the Threshold is set to 0, the Threshold
audio/sound is disabled and detector will
produce target signals sounds only.
If the Threshold is set to a negative value,
small target signals will not produce a signal big
enough to go above the Threshold of audibility.
If the Threshold is set to a positive value,
the detector will produce target signals
and a Threshold sound.
Press MENU SELECT and choose
Threshold.
Use the + and buttons to select a
suitable Threshold level.
Press PINPOINT DETECT, to return to
detection.
The tone of the Threshold can be
adjusted in Prospecting Mode only
(Threshold Tone, pg. 38).
The Threshold volume should be set to
the preferred level. It is important to note
that small surface objects, as well as large
deep objects, will produce very small
changes in the Threshold sound. It is
therefore important to set the Threshold
control correctly to ensure that these
targets are heard. Try experimenting
with known targets to assist in setting
this control.
Inaudible
Target #1
Target #2
Audible Target Response
Threshold
=
Volume
= 30
Target #1
Target #2
Audible Target Response
Threshold
=
Volume
= 30
Target #1
Target #2
Audible Target Response
Threshold
=
Volume
= 30
When Threshold and Volume settings are used together,
there is greater control over target audio response.
‘Blanking’ (No Sound)
Threshold
Threshold
Normal Signal