White’s Electronics MXT Pro - Manual (Page 28)

2
Chapter MXT Pro Controls
Threshold Control-
The THRESHOLD control sets the loudness of the back-
ground “hum” or edge of sound. This background “hum”
should normally be maintained during searching. In order
to hear the tiniest and deepest targets the THRESHOLD
“hum” should be set at the faintest audible level. It can be
slightly scratchy, chatter or static like but it must be constant
so as to not miss that small or deep targets. At this point, we
can’t recommend too highly the advantage of using HEAD-
PHONES. With HEADPHONES you can lower THRESHOLD
“hum” levels, and hear the faintest of target signals while
canceling out environmental background noise and improv-
ing concentration.
Threshold Adjustment-
The MXT Pro has an improved microprocessor driven
THRESHOLD control that is adjusted with a single turn. It
does not, therefore, require a 10-turn pot for precise adjust-
ment. Digital software provides much higher resolution, thus
you can set the “hum” faster and more accurately. Set the
knob all the way to the left or counterclockwise and then
rotate it clockwise until the faintest audible level of “hum” is
attained (edge of sound). If the “hum” disappears for any
reason (other than bumping the control) you may be either
swinging the coil too fast or your GAIN control is set too high,
or in the prospecting MODE you may need to increase the
speed of SAT.
Silent Search -
With microprocessor driven THRESHOLD controls argu-
ably skillful operators can “cheat the system” and use silent
search with high performance results. Once the threshold is
found, edge of sound, setting the Threshold control slightly
counterclockwise achieves silent search where no threshold
hum is heard during searching. By further optimizing Gain
to radical levels, much of the resulting noise can be hidden
under the Threshold and thus produce good field results.
Best reserved for more experienced operators, a balancing
act between higher Gain V.S. the stronger response required
to surpass the threshold setting, must be achieved and
understood.
THRESHOLD CONTROL
“HUM”