What is Reactivity and what are the advantages of this setting?

[FORUM XP]

Reactivity is a vital setting that determines the detector’s performance in terms of speed of analysis and selectivity. It regulates how quickly a device can be reactivated after passing over one target in order to be ready to distinguish the next one.
If a soil contains a great deal of iron, hot rocks or other mineralised debris, soil penetration is generally reduced, as is a detector’s ability to identify targets similar to iron.
In these conditions, DEUS enables you to select a high degree of reactivity which will help you speed up the analysis of signals.
On the other hand, if the ground is ‘clean’, it is better to reduce the reactivity and sweep more slowly, in order to be more sensitive to deep masses and obtain more thorough penetration.

Users familiar with the Gold Maxx Power have already had a foretaste of the reactivity of XP’s detectors. And even though DEUS is a particularly fast and selective detector, you now have the option of adjusting the reactivity setting to make it even more selective!

By way of example, and to help you better understand the reactivity levels available, you should note that the reactivity of most detectors on the market is generally only equivalent to level 1 of the DEUS. This is true, for instance, of the Gold Maxx and earlier XP models. The Gold Maxx Power has a reactivity equivalent to level 2 of the DEUS.

Most likely finds with the recommended settings are as follows:

0: Large masses and coins, in ground uncontaminated by iron.
1: Large masses and coins, in ground with little iron contamination, and general use.
2: General use, and mineralised soils contaminated with iron.
3: Difficult soils contaminated with iron, hot rocks, etc.
4/5: Very difficult soils, highly contaminated with iron and hot rocks, sensitivity to small targets.

NB: Higher reactivity levels (3, 4, 5) enable the detector to tolerate fast sweeps better.

In terms of pure performance, the greatest detection ranges are obtained with low reactivity levels. However, you will find more targets on difficult ground with medium or high reactivity levels. So do not just rely on performance in optimal conditions.

Depending on the reactivity level, you will notice that the length of the audio signal varies when it passes over a target:
low reactivity (0, 1) = long sound
high reactivity (3,4,5) = short sound

Evidently the length of any false signals – the crackling of iron for example – will vary proportionately as well.
You are therefore advised not to constantly change the reactivity level, as this may interfere with your ability to distinguish good and bad sounds.