Yes Lawrenzo, you hit the nail-on-the-head....... again! Set-up config is critical. The 6" dime should be easy for most any detector; however, due to its handicapped status...... several things must occur.
For purposes of 'appreciation'....... let me explain some other things =
Most all other detectors could not even "partially" or "start" to report/detect this dime. Especially concentric coil equipped units. ((( You are starting to see just exactly how critical a elliptical DD coil is ))).
The Explorer (with its concentric DD) audio will remain 'in-the-null'.
The old Soverign XS with the old 8" pie-pan CoinSearch DD coil JUST STARTS to 'grunt' on the dime. Hence; my respect for that old coil.
The T2 will acquire the dime..... but in a ratty/non-positive/non-'lock-on' fashion....... and many folks would not dig the dime, , especially if they are 'cherry-picking'.
The performance of the F70 is nearly in the same fashion as the T2. It will acquire the dime..... but audibly sound 'smeared'.
And now; the F75. The F75 audio is very discernable..... very positive audio ID. The VDI jumps quite a bit..... but the audio is 'positive'. This is with Sens '99', Disc '0', PF or DE, and 4-tone. If I invoke BC mode.... the dime completely disappears. If I select monotone; Disc must be on '5' or '6'. With Disc '5',,,,, the dime is a no-questions positive, hard hitting audio.... but the nails are slightly more than a snap-crackle-pop. If Disc is on '6'.... the audio duration length is quite a bit shorter on the dime...... BUT the nails nearly completely go silent....... giving the dime a much greater discernable audio differentiation...... even though, quite a bit shorter audio presentation. Your ears/brain discern better with this greater differentiable scenario.
Interestingly; The T-square (T2) is a 10" dime capable unit, , , yet it badly struggles with the 6" dime complex target scenario. The extra punch of the F75 is highly prized. ---One particular old home site..... I clearly remember (and head-to-head tested)..... finding dozens more coins on the front lawn and left-side lawn with the F75.... that the T2 missed. Most of the coins were only 7" - 8" deep. The T2 would/could not detect these coins. Head-to-head. The F75 acquired.... but was struggling.
Shambler; I understand exactly what you are saying; however, you are MUCH better off .... being armed with 'realistic' length audio presentation...... vs. ....... artificially lengthened/enhanced audio. While the detector is reporting a artificially lengthened audio report whilst the coil is still covering more/additional ground, it'll THEN miss adjacent targets. And if there are two targets in extreme close proximity........ say; separated by only 1" or 2"..... with the first target being a high-tone aluminum screw-cap....... and the second target being a mid-tone gold coin; ; ; .......... but the unit decides to artificially lengthen the high tone...... and continue to report a standard full-length audio high tone...... whilst the coil continuing its motion...has now passed over the mid-tone gold coin..... which may/may-not give a response. And layered audio via stereo channels in a set of headphones.... could still be confusing..... possibly misleading.
It is better to learn the Soverign coil 'wiggle'...... employed on the F75 platform. Simply slowing down your coil sweep speed.... will lengthen audio duration... in linear fashion, , , no fancy electronics reqd. Contentions with masking culprits, I'll always want realistic audio dialog.
Tom