Here is an explanation of these settings, plus why pro’s use the extreme settings they do.
Higher adjustments are used primarily to consistently find both large and small gold in highly mineralised ground.


Coil / Rx Setting = Mono with a Mono coil.

We use the Mono setting with an 18”in NF Mono coil, M/Lab recommend using the Mono position too, not the DD position.
It has been found that to exceed this coil size for general prospecting, brings in EMI to an unacceptable level.

Ground Balance = Fixed, when using Enhance.

Fixed is recommended, after a careful G/Balance, GB is crucial in Enhance timings.
Even though the machine sounds GB'd, get into the habit of G/Balancing often.
Using Tracking can G/B out a faint small or deep target in 2 sweeps of the mono coil.

Soil Timings = Enhance with a Mono on hot soils.

Enhance is the best thing the 4500 has going for it in hot ground conditions, this timing gets most of the missed gold, (Large & Small), plus its quiet running lets you hear the faintest of responses.

Search Mode (Front End Cap) = Deep, in deep ground. (1’ft to 3’ft+).

We recommend this mode with the Digital settings below, as it has proven to us that the 4500 differs from what settings we had used on the GPX 4000.

Digital Menu

Backlight Off (Unless detecting at night)

Battery Test = 8.0+V (Recharge battery each night)

Volume Limit = Headphones = 15 ------ Speaker with adjustable amp. = 18

Experiment with this, don’t go below 12. It can also be run at 20

GB Type = General

Specific is too much of a handful, its use is only recommended in highly magnetic soil conditions.

Man Tune Find the best response over a known deep buried target, try in the range of between 80 to 110, all machines are different to get their ultimate frequency position. (It does make a difference).

Only tune out EMI up to 5 digits either side of your detectors best setting.

Have the machine always set on Man / Tune while detecting, as the EMI interference waves come through, reach down and adjust the right hand knob a few digits up or down to get a quiet frequency. We don't use the auto tune button.

General Menu

Motion = Slow -------- or use (Very Slow), if there is bad EMI.

RX Gain = 12 for the deep quiet ones, if EMI is nonexistent, try 13.

Why would you not have your detector near to maximum gain?
When it has been proven to produce large gold at depth.

It also gets the Fly Sh!t down to . 2 of a gram with this gain setting.

Audio = Normal -------------- (Less EMI and spurious noises).

Do not use Deep setting here when Deep is used on the F/E Cap, as the Signal to Noise ratio is infringing on the faint responses.
With the 4000 you could use Deep / Deep, but on the 4500 it's noisy.

Audio Tone = 33

A lower tone is more suitable for the low growly deep faint signals; it is also less annoying to the ear over many hours of detecting.
The small gold signals still comes through with their rising pitch.

Stabilizer = 11

Factory pre set is 10, with what you are looking for, (better size gold), a tweak up is better than down.

Signal Peak = 19

This helps to determine target responses from ground signals, set high; it provides a sharp clear target response with a quicker diminishing fall away.

Target Volume = 10 for headphones, ----- 12 when using an external speaker amp with adjustable volume control.

Response = Normal

This gives the best chance on the smaller bread and butter gold, usually with a sharp high rising response. Yet Normal response still responds well to the large deep gold, with that unmistakable dipping growl.

In fact the majority of nuggets, say from 5” or 6”inches deep, will give this reverse pitch dipping signal when using Enhance.

Most ground noises give a wide rising pitch signal, this is usually not consistent from all angles of the coil sweep, and with practice many can be eliminated.

When in doubt have a dig, also after rain with the dry & wet patches, or wet charcoal under the surface, you do get some dipping ground noise responses, these tend to make you dig more, but better to be safe than miss one.

Tracking = Slow.

The reason: - When in Fix and your Ground balancing, the switch holds it in tracking for a short time.
Using Slow Tracking restricts the EMI noise at this time and helps the GB process.

Iron Reject = OFF It will not work with a Mono coil

Remember the ground conditions have to be of a highly mineralised and variable nature to use the Enhance timing, so if the conditions are mild, you should be using Normal timings for better depth.

To get the perfect G/Balance

Note; Keep the coil parallel with the ground during the pumping procedure.
Keep your coil stationary 30mm above the ground. Hold in the green button on the handle, now pump the coil using small even movements of about 30mm to 40mm up & down, (at this height above ground).

Bring the coil down slowly to the lowest point of the pump, (30 mm from the ground), be sure to hold it really steady when you release the button.

Never release the Q /T Button whilst the coil is moving or twisted, as this can affect the accuracy of the G /Balance.

Be prepared to go through this same procedure 2 or 3 times to get it just right, as sometimes conditions make it hard to get it to G/B the first time.