Yes TH and Iron...
The Minelab multiple-freq metal detectors DO NOT achieve any more depth, success, or advantage over those with 1, 2, or 3 freqs, otherwise the Fisher F-75's, Nautilus's, and Garrett 2500's, 1200's, Nexus, GoldMaxes, T-2's, my super-Compass that I boosted the power in, my old Garrett Deepseeker with it's single freq, etc would not be able to keep up with (or out-do) them.
Minelabs with so many freqs riding piggy-back and later converted to useable and transformables do so for reasons of selling points, (mostly) because otherwise they would have a superior detector running one or two freqs, and they do not. In fact there are federal regulations as to how much power a metal detector is allowed. This is why in nearly every case save for a bit of well-engineered circuit design there is seldom more than 1" difference depth between a $500 metal detector and a $1,500 one, single freq, or 128 freq. I know, I have tested them side-by-side and there really is little to zero difference.
In an even more simple way of putting it; "Why build something with multiple or many multiple frequencies and many, many different coils when we can see already that an 11" DD coil running in 1, 2, or even sometimes 3 freqs is not just keeping up with larger and smaller coils and multiple frequencies, it is also outdoing most of them". And a small coil for nugget hunting should take care of the really small stuff too. Right now, the 11" DD is the azimuth of searcoils, bar none, finding very tiny stuff to very large stuff, quite easily. And it's because it took nearly 100 years of experimentation to get this far. It's called "progress".
That's why we don't really need so much extra weight and extra junk to haul around with us. Look at the Tesoro Tejon with it's simple operation and how deep it goes in mild to medium soils, isn't there some sort of explanation for it? And isn't it lightweight too? It certanly whipped my Sov and the various Explorers I put it up against, and in all different soils. Yes, the difference wasn't but an inch or so, but why bother with many freqs when they aren't needed? It just isn't logical at all. And how about the F-75 and T-2, they don't need a bunch of different frequencies or coils to operate well. And how about the Nauties, simple, yet effective? Why should they be able to walk all over most everything out there for all-out depth? Sure, one inch is about all they get extra (at best) but that's not the issue here, it's about whether or not we need a lot of frequencies or not.
A proponent of Minelab would have some sort of way to try to explain his or her way around that question - but the truth always speaks for itself.
In a short while we won't even need all this hardware anyway, we will be using nano-human-tissue technology with the operation of metal detecting incorporated within out own human flesh. Even now we (science) have developed mental control over certain mechanical operations, and we don't have to touch a thing to do some tasks, we merely "think" to do them.
http://www.sciencedaily.com/releases/2000/11/001116080512.htm
Question: Why do you think that metal detectors have changed very little in the last few years? Is it because something is about to change? Or is it because of money? I think we all know the answer.
LL