I only use the 3-Tone 'Park' mode when hunting in trashier conditions, where most commonly-encountered coins are in the surface to 4" range. For most o that I am eagerly awaiting the release of smaller-size coils for the Simplex[sup]+[/sup]. They'll work better with the quicker-response of that mode. For now, however, and because we're into wintry weather, the bulk of the detecting I have been able to do is in bigger-size parks, hunting th more open middle areas and places where I can encounter some deeper coils. I do use the Threshold-based All Metal mode occasionally, just for 'scouting' an area, but that's only occasionally. Even thought it is an All Meta mode, the auto-tune used requires a faster sweep speed to achieve any discernible detection depth compared with a model w/o auto-tune, Most of the time I have found both of the 2-Tone Discriminate modes to provide a little edge when nit comes to coin depth.
That leaves us to choose between the Field mode and the Beach mode. I live on the far side of Oregon away from the salty coastline, but so far I am still preferring the Beach mode about 55% of the time and Field mode the other 45% of the time. Often, when I have located a target, I make a quick 2-press of either arrow and change to the other mode, just to audibly check the targets in the other audio. I go by audio response the bulk of the time when making a 'Dig' or 'No-Dig' decision.
As I mentioned, I like the 3-Tone Park mode in places that are well littered, but for most of my hunting in open areas, and when iron nails are typically my primary junk-trash encounter, I prefer to hunt in a 2-Tone mode and listen to everything. In all three Discriminate modes I run without any Disc. notches rejected, and I also keep them at Full Sensitivity unless EMI causes me to back it off a little. I can't adjust the Iron Audio Volume in Beach mode [size=small](but wish I could)[/size] and have it set at 1-Bar in Filed mode and 2-Bars in Park mode.. I have the Simplex[sup]+[/sup] set at Full Volume and keep the Frequency Shift at the default 'F2' unless very necessary.
Both the Field mode and Beach mode are deeper and very close to similar. There are times when most of the targets I encounter are in the surface to maybe 5" range and I like to use the Field mode and take advantage of hearing the VCO enhanced audio. But most of the places I am hunting out in the wide-open park have coins in the 4" to 8" range, and for that I definitely prefer the Beach mode with the Non-VCO audio. Maybe it's me, but I like the Beach models audio Tone which is similar to the Mid-Tone in the Park mode, and without any VCO processing at work and a different tone in Field mode, I tend to hear the deeper targets just a little more clearly. Better defined audio report in Beach mode, for me, on the deeper targets.
Also, when I have compared the audio I get on those deeper coins I have been finding, I feel the Beach mode hits them a little better at-depth with a modest or more comfortable sweep speed. In the Field mode, [size=small](and I think it's due to the VCO and other audio processing)[/size] it seems to need just a little bit faster sweep speed to hit on the deepest targets. The occasional nails or bits of iron debris are no issue, but if I get into an annoying amount of nails or other iron, then I quickly switch to Field mode to take advantage of the 'Low Iron-Audio Volume' that is set at '1-Bar.'
Monte