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Simplex+ Notch


Active member
The Simplex+ manual calls it 'Notch Discrimination'. I was talking to a guy and he said it was just 'discrimination' and using any woukd decrease detection depth. Since all detectors I have ever had that used discrimination the setting started at 0 up to a much higher number. No detector that I have ever owned with just discrimination had any notches. Several detectors I have had or still have have both discrimination and notch features. So, I was thinking that what Nokta Makro calls 'notch discrimination' may in reality be 'notch' and not actually discrimination. I need someone that can fill me in on this. I know that discrimination can cause loss of depth and notch usually does not.


You should probably ask Nokta. The Deus notch does not lose depth so not all detectors are the same, ask an expert, or just try it with a test target.


Active member
Discrimination is discrimination
Notch Discrimination is a set point of discrimination.
Not on the Deus it isn't. There is discrimmination and then there is notching. Discrimination looses depth, biut on the Deus, notching doesn't.. I fired off a question to Nokta Makro and maybe they will give me an answer as to how they handle. this on the Simplex+. Thanks


Well-known member
Well, I think some things need clarification because 'Notching' aka 'Notch Discrimination' aka 'Segment Discrimination' is just that ----- Discrimination. It is not the same as a progressively increased setting, be it manual with a knob control or using a touch-pad to increase the setting like some models used to use .... and some still do. There have been different approaches taken in how manufacturers design their Notch Discrimination function. Follow this or a moment:

Discrimination: A method used to 'reject' an object or conductivity range so it isn't 'detected' or 'heard.' Methods used: A variable control that can increase the level of 'rejection' to Discriminate or Eliminate a target from responding by increasing the control from Low-Conductors, such as Iron, on up through the Foil Range, a low-conductive coin like a US 5¢ piece, then Pull Tabs, Screw Caps, US Zinc Cents then Copper Cents and on up through Higher-Conducive coins like a US 10¢, 25¢ and 50¢ coin. This is the original Discrimination design that relied on a progressive, low-to-high, 'rejection' based on a target's conductivity.

Notch Discrimination: As originally designed, this was a separate variable control that allowed the user to adjust a Notch Disc. control just like the Primary Disc. control, and the design had a dedicated 'window' or designed range of 'rejection' or 'Discrimination' that allowed the user to increase or move that 'window' of Discrimination' in order to Notch Reject, or Notch Discriminate, a manually-determined range of unwanted trash. For example, it could be set just a bit higher than a US 5¢ coin to Discriminate or Notch-Out unwanted Pull-Tabs, or most of the older ones we used to have.

We had this type of Notch Discrimination in the '80s and, for those who liked it, it was a functional design and the operator could usually control the set point for the lower-end of Notch Discrimination and the upper-end was determined by a 'window'. That was often a preset design, but on some models the operator could adjust for a wider or narrower window of Notch Discrimination for a desired rejection range.

Modern Discrimination 'Notches' or 'Segments': About thirty years ago we saw our first detectors that used an LCD type display and featured an array of 'Segments' along the upper-portion of the display. Those Segments provided the user with preset Discrimination 'Notches', thus Notch Discrimination, and the operator could Accept or Reject ... aka Listen-To or Discriminate, various metal targets based upon their Conductivity, just like we used to manually adjust. Except now, the manufacturer determined what reference point on a VDI (Visual Discrimination Indicator numeric scale) they wanted to Reject then Accept, or to Stop Detection and Start Detection, based on a target's conductivity. Plus, instead of have one variable manual Notch Disc. control, they provided a full-range set of 'Notches' so the operator could 'reject' or 'Discriminate' a number of different 'windows' of conductivity instead of only one Notch. window..

This is still the same 'concept' but sometimes with a different approach to addressing Notch Discrimination, or Notch Rejection all the same thing. In this case, the Simplex + DOES have Notch Discrimination, and the operator simply selects the Notches or Segments that associate with the annoying trash they want to Discriminate aka Reject. But here are some modern differences. In those earlier days of Discrimination and to include a lot of what we still use, if you have the Disc. level adjusted close to the detection point of a desired target, you might lose some depth and responsiveness to that target. Why? Because you've also adjusted to be just-barely Accepting the good targets.

With most of today's modern detectors we have a numeric VDI read-out so try this. Let's say you have a good coin that produces a VDI or '57' and your Discrimination is adjusted low at a VDI of let's say '15.' Place that desired target at a reasonable depth to check it with your detector and coil and get it positioned close to the maximum depth you can still sweep over it and get a decent audible response. Now, maybe it gave a '57' VDI on an air test or on the ground, but now buried you hear it and get a VDI of perhaps '51' instead of '57' due to the ground mineralization. Good target, good hit at depth and a VDI of '51.' Now, increase your Discrimination to reject perhaps '48' or '50' on down. Check the buried coin. Get a good hit and VDI response? Often, NO, because the Discrimination was too close to the target's Accept/Reject point. To get a good signal again the Discrimination needs to be lowered to a lesser VDI point. In short, you often can not encroach on a target's conductivity with a lot of Discriminating circuitry designs w/o losing depth and target detection.

Now, let's get even more 'modern' with Notch Discrimination. Because we have gone into this world of digital circuitry design and so much is done 'by-the-numbers' internally in circuitry, some of the Notch Disc. segments have been designed to Discriminate an audible target response if it falls in that Notch reject range ... OR ... some Notch circuitry designs are using more of a clipped configuration such that if a VDI response for a particular Notch segment runs from let's say '6' to '10', then any target that falls within that VDI range you will not hear, just as if it had been rejected the old-fashioned way, but in new designs the target is still detected, like before, but the modern circuitry simply turns 'Off' the audio or Volume for any target in that Notch Disc. range. It's there, you just don't hear it.

Still, either approach used for 'rejecting' a particular segment is still Notch Discrimination. Some models use a limited number of Discrimination 'Notches' such as 8 on a Fisher F5, while others, like the Makro Racer 2 or Nokta / Makro Simplex +, use more Notch Disc. segments, and, by doing so, it means each Notch represents a smaller amount of VDI numbers or a narrower Notch Disc. 'window.' On a positive note, with the better detector circuitry designs in use today, I find that when 'testing' a Notch Disc. circuitry (and I only 'Test' them because I never use Notch Discrimination) they seem to not lose depth and performance like they used to.

Yes, your Simplex + doe feature Notch Discrimination. Look at the display adjustment right after Iron Audio and it is called:
Notch Discrimination Discriminates Target IDs of unwanted metals.

Or, just tun to Page 13 in the Simplex + User Manual:

Notch Discrimination

Use the notch discrimination setting to eliminate unwanted metals from detection such as trash. SIMPLEX+ has 20 pixels or "notches" of discrimination, shown under the TARGET ID scale with small boxes. Each box represents a group of 5 IDs (01-05, 06-10, 11-15 and so on). Any combination of these boxes can be rejected or accepted based upon your preference. The boxes rejected will be highlighted in black.

After this, the device will not provide any audio response for metals ..
.. that have been Notch Discriminated.

Sorry to ramble, but a lot of people still do not understand 'Notch Disc.' so there you go and I hope this helped.