The two machines I used were my Garret Ace 250 fitted with my 13" Ultimate Coil and my XP Deus 3.2 fitted with the Standard 9" Coil.
Why did I bother doing this test, well,,,, like a lot of detectorists, I wanted to justify to myself why am I now using a £1,200 machine, when I started out detecting using a machine costing only £180.
Very briefly my story goes like this:
Excellent start to metal detecting. Finding stuff and getting hooked on the hobby.
Upgraded the 9" coil to a 13" coil. Cost £120.
Excellent, digging more and deeper. I looked at it as I now had a machine costing £300.
Upgraded to a Garret AT Pro. Cost £595. Kept the Ace 250 for a back up machine.
Poor move. Found the Ace 250 with the 13" coil performed just as good if not a little better than the AT Pro. Sold the AT Pro and went back to the Ace 250.
Upgraded again to a Nokta Velox One. Cost £595. Still kept the Ace 250 for a back up machine.
Good move, I liked the Velox One. Though I didn't see any more depth than my Ace 250 with the 13" coil, I did like the way it sounded and I seemed to be able to tell different signals apart easier.
Had a problem with both my arms and found the Velox too heavy for me and sold it on.
Upgraded again to the XP Deus, which I am still using. Cost £1,200. Still have my Ace 250 as a back up machine.
For me and my arms an excellent move. Reason being its so light. Also love being cordless.
Depth wise, not much difference than my Ace 250 with 13" coil.
I will admit I'm obsessed with depth, I want to go as deep as possible so as to know I'm not missing anything. I used to think the more a machine cost, the deeper it will go, hence my upgrades. But when I look back I can easily see that's not the case. All I seemed to have got for more money is more bells and whistles, but not the depth I was after.
I now compare metal detectors to cars. A Fiesta is a simple car compared to say a Merc with all its bells and whistles., but they both drive you from A to B. It depends on what you want yourselves, myself, I like simple and depth.
So in a nutshell and back to my tests, I can only justify to myself I have paid an extra £900 for a machine that's friendly on my arms and being cordless. But I'd sooner have extra depth.
Filled an 18" deep plastic planter with top soil bought in from a garden center. I wanted good topsoil as I didn't want any small metal pieces contaminating it and plus the soil in my garden was contaminated and stoney.
As I said above, both coins were buried in same soil in the same environment. At 6", 8", 10" and 12".
At 6" with both machines set at Max Sensitivity and no Discrimination (Ace in all metal mode), (Deus tested in all factory programs with no tweeking), both coins were picked up easily with good clear signals.
At 8" with both machines set at Max Sensitivity and no Discrimination (Ace in all metal mode), (Deus tested in all factory programs with no tweeking), both coins were picked up easily with good clear signals.
At 10" with both machines set at Max Sensitivity and no Discrimination (Ace in all metal mode), (Deus had to be tweeked), both coins were picked up but with weaker/poor signals. It was a case of should I dig or not.
At 12" both machines indicated that there was a target there but very poor signals.
After 12" nothing.
Yes, a very simple un-exciteable test I know, but it convinced me you don't get anymore depth for your money, just more comfort. My next couple of metal detecting trips I am going to use my Ace 250 for a change, just for my own curiosity. I'm wondering with all the bells and whistles that they could be making me miss finds. Time will tell...