With my Primary Detector set-up and for the types of sites I hunt, I opt for the ± 7X11 DD coils for more open areas with fewer targets. Yes, I know they can still do pretty well in a 'busier' site, but there are good reasons to opt for a smaller coils and different settings.
In a Sparse target site, I usually use the 2-Tone search mode, bump the Gain up to '85' and on occasion a little higher, maybe to '95,' and I leave the ID Filter at the default setting of '10.' I usually like to hear all, or most, of the targets at a site, and let my ears discern the differences in the audio responses. If I encounter a piece of ferrous junk, I can slow my sweep a bit more and carefully work the search coil around the offending metal to see if there is a nearby desired target ... even if partially masked.
In an Icky target site, I am encountering more targets that are more closely spaced. Targets might be ferrous based or non-ferrous, it doesn't matter, there are just "more targets" to deal with. In these conditions I often make a search coil change before any setting adjustment change, and I go to either the 5.[size=small]5[/size]X10 DD solid coil, or the must-have 4.[size=small]7[/size]X5.[size=small]2[/size] 'OOR' Double-D coil. Many Racer users buy the Pro Pack and have just the standard and small coils and those work fine as a team. If you also have the mid-size enclosed DD, it makes a fine option.
As you noted, when working in any dense target environment, 'depth' is not the big issue or increasing the Gain. Instead, the first thing to do is opt for a smaller coil, then adjust the settings for peak performance for the conditions encountered. In this type of busier target condition I think it is more a matter of which mode we prefer and how much junk we want to hear. I guess I could say that the environmental challenges could run from "kind-of-Icky" to "pretty-darn-Icky" and only we can determine that for ourselves.
As such, I might opt for 2-Tone or 3-Tone search mode, and perhaps leave the Gain at the default of '70,' or decide to bump it up or down depending upon my comfort level for the conditions. Often I leave the ID Filter at the default setting of '10' because that lets me hear almost all the iron targets present, then I can audibly deal with the ear-traffic. However, if it is on the closer to annoying level of nails and iron trash, I simply bump the ID Filter to '23' which is sufficient to reject most iron nails. We can't get rid of all of them, or those that are bent at odd angles and pose an additional challenge. I just use a setting of '23' and hunt away.
When I deal with a Nasty target environment, then I almost always use the smaller 'OOR' coil, search in the 3-Tone mode maybe 90% of the time, and go no higher than an ID Filter setting of '23' to reject most nails. AS fore the Gain, I always increase it when it is in my favor, but if conditions are more of a challenge, then I use the default setting of '70' or reduce it to the point I am comfortable with the results for the site I am hunting.
You can experiment with a lower ID Filter setting, but I seriously doubt you'll do any better. A '10' is ample to deal with ground and rocks and such, but still pass along most iron targets. The '23' I use works fine, and I seldom have any reason to set it higher.
Monte
