Minelab Manticore - Reference Threshold Tone; True Threshold Tone; Reference Threshold Blanking

CONTENTS
43
Audio Theme (Continued)
'REFERENCE' THRESHOLD TONE
The Normal, Enhanced and Depth Audio Themes use
a simplified 'reference' threshold tone. It is a simple
continuous background tone that blanks when a Rejected
ID is detected.
Without a reference threshold, a rejected target detection
would be silent, and you would not be made aware of the
target's existence.
For typical treasure detecting locations where there is
often a large amount of trash in the ground, constant audio
blanking may be disruptive, therefore using a Threshold
Level setting of 0 (Off) is recommended unless you want to
hear audio blanking.
Reference Threshold Blanking
When a Rejected ID is detected, the threshold tone ‘blanks’
(becomes silent) to indicate that a rejected target is
underneath the Coil.
If the Threshold Level is set to 0 (zero), you will not hear
the blanking of the Rejected IDs.
Audible Detection
Threshold tone
Target with Accepted ID
Target with Rejected ID
‘Blanked’ Detection
(no sound)
Time 
'TRUE' THRESHOLD TONE
The Prospecting Audio Theme uses a more nuanced, 'true' threshold tone which is recommended for gold detecting. A
'true' threshold tone can be adjusted to improve the audibility of faint signals from small gold nuggets. Unlike a 'reference'
threshold, 'true' threshold allows gold nugget signals to be emphasised in typically mineralised (noisy) goldfield soils.
Greater control of the target audio response may be achieved by adjusting the Threshold Level and Volume
settings together.
Too Low Just Right Too High
Audible range
Quiet signal
now inaudible
Loud signal
Threshold Level
Audible range
Threshold Level
Quiet signal Very loud
signal
Audible range
Threshold Level
Quiet signal
masked
Loud signal
just audible
If the Threshold Level is too low, the
variation caused by a small or deep
target may be inaudible.
If the Threshold Level is just right, it
should sound like a faint audible hum.
This emphasises variations in signal
response making targets easier
to hear.
If the Threshold Level is too high, it
can make faint targets more difficult
to hear above the threshold hum.