Metal detector discrimination, explained

Discrimination decides which targets make a sound. Garrett puts it plainly. In its words, Iron Audio lets you hear discriminated iron that is normally silenced, such as bottle caps or washers.

So a silenced target is still in the ground. You chose not to hear it. Garrett lists five search modes plus pinpoint for the ACE 400.

Some detectors discriminate with no number on screen. Under target ID, Bounty Hunter's page for the Gold Digger reads "None", yet it gives it All Metal and Discrimination modes.

There is no shared scale. Minelab's Equinox 900 scale runs -19 to 99 (119 segments). The X-Terra Voyager's runs 0 to 99 (ferrous 0-30). Garrett's ACE 300 and ACE 400 show 0 to 99, while the ACE 250 has an icon legend, no numeric ID.

Some scales add a second axis. The Manticore shows 2D IDs from 0 to 99 with ferrous indication, and the CTX 3030 lists ferrous 1-35 and conductivity 1-50. A number read on one detector does not carry over to another, even within one brand.

One range can also be cut finer. The Vanquish 340 reads -19 to 40 (5 segments). The Vanquish 540 covers the same numbers five times finer: -19 to 40 (25 segments).

Many models give the low end of the scale its own controls. Garrett gives the AT Pro 40 levels of iron discrimination and the AT Gold 44 levels. Teknetics lists 8 categories plus a notch for the Omega 8500. Minelab's Pro-Find 35 pinpointer flags ferrous targets with a Ferrous tone ID.

Within one Nokta range, the settings grow with the model. Nokta's chart lists no notch or iron filter for the Score. The Triple Score gets a notch, an iron filter from 0 to 9 and bottle cap rejection.

The Equinox 900 and the Manticore both keep an All Metal mode. Use it when you want no target silenced, or to hear the whole site before you set discrimination.

Discrimination sorts by signal, not by value. It says nothing about how far a detector reaches: for that, see our depth guide.