Independently researched Practical Guide
Metal Detector Discrimination Explained
Discrimination rejects electromagnetic response ranges; it does not identify objects. Every silenced range can contain valuables, especially gold jewelry, unusual coins and targets beside iron.
Bottom line
Use discrimination to manage workload—not to promise treasure-only digging
Begin with a factory pattern or All Metal sample, learn the site’s actual trash, then reject only recurring nuisance ranges whose loss you accept. Use iron audio, cross-sweeps and a smaller coil before applying extreme notch.
Field guide
Starting points and hard limits
| Situation | Baseline | Action | Caution |
|---|---|---|---|
| Modern coin cherry-pick | Coin factory pattern | Moderate rejection | Jewelry and odd coins may be lost |
| Jewelry search | Open non-ferrous range | Low iron rejection | Expect foil and tabs |
| Dense nails | Small coil + recovery tuning | Moderate ferrous control | Max filters can mask coins |
| Historic mixed site | All Metal/open Custom | Dig broad repeatable signals | Context may matter more than ID |
Method
Use a controlled workflow
Sample openly
Dig representative signals to learn the site’s real overlap.
Separate iron tools
Iron Bias/filter, ferrous limits and notch do different jobs.
Reject measured ranges
Change one segment and test known valuables beside trash.
Recheck masked targets
Cross-sweep and expose rejected audio before leaving.
Decision analysis
What actually changes the result
Notch removes conductivity bands. It cannot know whether a response is a tab, ring, token or coin with the same electromagnetic signature.
Iron Bias and Ferrous Limits are classification controls. They change how ambiguous mixed responses are treated; they are not the same as rejecting a numeric ID column.
No discrimination is the only path to every possible target. Minelab explicitly describes factory patterns as a compromise between recovering good targets and ignoring junk.
FAQ
Seven questions specific to this page
Does discrimination identify the metal?
No. It rejects response ranges based on ferrous/conductive evidence, not object composition.
Can I notch every pull-tab ID?
Yes technically, but doing so rejects gold rings and other valuables in the same range.
Is Iron Bias the same as notch?
No. Iron Bias changes ambiguous ferrous classification; notch accepts or rejects target-ID segments.
Does more discrimination reduce depth?
It can reduce usable depth because weak/deep targets often classify less consistently and may be silenced.
Should beginners use All Metal?
Use it periodically to learn iron context and site density, even if a factory pattern is easier for hunting.
Can a small coil reduce trash without more rejection?
Yes. Its narrower footprint can separate adjacent targets while preserving their individual signals.
What is the safest discrimination strategy?
Start open, sample the site and reject only measured nuisance ranges whose valuable overlap you accept.
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Use evidence, not copied numbers
Record the detector, mode, coil and conditions behind every useful result.
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