Garrett GTI 2500 Owner's Manual page 71

simplify audio detection by eliminating
virtually all targets as deep as the first
four inches beneath your coil, where
most trash metal will be found. When a
metallic object is accepted, the detector's
sound will, of course, increase from your
threshold level. Some rejected targets,
however, may cause the audio to "break
up" or sound erratic. This is generally a
response to shallow trash targets and can
be remedied by raising the height of your
searchcoil when scanning or by using the
surface elimination feature.
Another indication of a reject target is an
audio signal as you scan one way, and no
response when scanning from the other
direction. If you encounter a large target
and scan too close to it, the detector will
give an audible overload indication, which
sounds like a buzzing alarm.
Setting Sensitivity (Depth)
Garrett engineers designed your GTI 2500
for maximum detection depth power, but
you may not always be able to search at
100% depth just as you rarely can (or,
even want to) operate your automobile
Graphic Target Imaging 2500 - 71