It is an eternal debate, what is the best DD disk for the XP Deus, the 9 inches or the 11 inches?
Already, it is known that since the release of the 11 inches, the 13/11 inches has become useless since the performances are the same for a lighter weight advantage.
For a comparison between the 9 inches and 11 inches disc, most people agree that the 9 inches is:
– better on ferrous and polluted grounds,
– better near the rivers,
– more accurate in targeting,
While the 11 inches is:
– best in clear (unpolluted) ground,
– quasi equivalent in depth research,
– convering a larger area.
Indeed, the DD disk 11 inches requires a ground not very ferrous and not polluted. It also allows on average to find objects only 1 inch deeper than the 9 inches disk. This difference is increased when it has rained, it can reach 2 or even 4 inches according to the zones. It is more erratic near the rivers since it sounds intermittently on the pebbles rich in minerals (the 9 inches has some difficulty, it must be said, but much less). And finally the 11 inches scans a larger surface, this is its main advantage, so it will miss the less targets.
The 9 inches is more accurate and saves time finding objects.
Most diggers agree that the two are complementary.
Given this comparison, it could be said that in the south of France (for example), and near the mountains, the 9 inches will be more effective. While in the north with loose soil and without too much iron, the 11 inches will be ideal.