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Tone
Adjusts the tone of the threshold. The user may set this to the preferred
tone, e.g. the tone at which the operator’s hearing is most sensitive.
Some people will find that their hearing is best in a particular range of
pitch, setting the tone control to this pitch will mean that the operator is
listening more acutely, and probably more comfortably.
At minimum position, threshold gives a low tone. Turning clockwise
increases the tone to a higher pitch.
Operating Instructions:
Adjust the Tone control until the threshold
is at a comfortable tone for your hearing then test it on a couple of small
targets. Adjust until you obtain the best signal response.
HINT
Setting Tone to a high pitch may be more fatiguing, but is more
suitable for identifying soft target signals.
Figure 4.10
Tone control
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GP 3500
www.minelab.com
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Figure 4.11
Signal control
Signal Audio
Human hearing is sensitive to changes in tone, so the operator is more
likely to hear a target signal when both the volume and the tone change
rather than volume alone. Interpretation of the target signals involves
understanding the difference between the rising and falling tone and
volume of the threshold in response to different targets.
The Signal control gives the operator the ability to choose between a
target signal that has a large variance of tone, or one which has less
variation. High variance can give the operator more signal definition to
interpret, however in highly mineralized ground this high variance of
signal may cause confusion and make the detector appear noisy so a
lower setting may be preferred.
The Signal Audio control adjusts the pitch response of the target signal.
As a target is located, the target signal will change tone. For small
targets it will often drop to a deeper pitch then rise to a higher pitch.
The range of variation is controlled using the Signal knob.
Operating Instructions:
In
Figures 4.12 and 4.13
the curving line represents the high/low pitch
response to a target. The dotted line represents the threshold tone.
•
At minimum position the high/low pitch variance of the target signal
is reduced.(see fig. 4.12) So target signals are more monotone.
•
At maximum position the high/low pitch variance of the target signal
is increased.(see fig 4.13) So that there is a large variance between
high and low pitch of the target signal.
Figure 4.12
Reduced pitch variance
Figure 4.13
Increased pitch variance
