On that same page where it states the Golden µMAX uses the ED120 Discrimination, it also tells you that the #1, or lowest tone, of the device is a lower tone for Iron and small Foil. Well, you can't get iron targets, generally, with an ED-120 Disc. range of acceptance. I know when they first came out I called that to someone's attention down there, because after trying mine it didn't have the ED-180 range of the Eldorado or Compadre, but it had more than the Bandido II µMAX, Silver Sabre µMAX, Bandido, and other ED-120 ranged models. I believe it has an acceptance range more like about '165' or so, kind of similar to the Vaquero.
As long as the ferrous [size=small](magnetic)[/size] metal twist tie or a common paperclip or similar wire-iron type object it, and he Discrimination is low enough to accept all or some ferrous-range metal targets, it will produce the low-tone audio as long as the wire is straight or in a Z shape, and S shape, a U shape, or a W shape. But if you fashion it so that the ends connect into an O shape, then you will not get the low-tone iron audio response with a direct, center-axis search coil sweep.
That is because you changed the conductivity of the metal object. Just the opposite of taking a nice solver or gold ring that gives a nice-and-proper signal, then you cut the band so it doesn't form and completed/connected O shape an the signal is then very degraded, or reduced conductivity.
Quite a few Owner Manuals fro various manufacturers through the years are note prepared by someone who uses metal detectors and knows the meanings of terminology. They often just cut-and-past some info from other manuals, such as suggesting the Golden µMAX is an ED-120 range if acceptance like some other models rather than a broader-range as it was designed. So, as long as you are adjusted to the minimum Disc. setting, then most accepted [size=small](and unaltered by man)[/size] ferrous targets should produce the Low Tone iron audio response.
Maybe I better correct that, because many multi-tone detectors I use, such as a Nokta FORS CoRe or FORS relic or Impact or Makro Racer 2 or Gold Racer and some others have a digitally designed circuitry and can generally Low-Tone for Iron and produce a Mid-Tone or Higher-Tone for small Foil, in a clean, air-test environment. The Golden µMAX Owner Manual states:
"The Golden µMax is designed to help detectorists improve their coin shooting finds. It combines three systems to help identify targets before they are dug. First is Tesoro's tried and tested ED120 discrimination. Offering 120° of discrimination range covering a broad spectrum of unwanted targets. Second is a four tone audio ID. The tones cover 1) iron and foil, 2) rings, nickels and some pull tabs, 3) most pull tabs and screw caps, 4) pennies, silver coins and jewelry. A special tone for targets that are causing the machine to saturate is also included. Third is a Notch Filter discriminate. Notch discriminate will allow you to tune your Golden µMax to discriminate out most pull tabs while keeping the nickel and gold ring. It is user adjustable to fit the hunting styles of most detectorists."
If you don't mind, let me insert the fact that when the first Golden µMAX was introduced I was still a Tesoro Dealer and was eager to see if they had 'cleaned up' the iron target audio ability. I really like the concept of the Euro Sabre, but wasn't pleased with the 4 different Euro Sabre models I had because the ferrous/non-ferrous region was sort of a mushy-sounding or blended audio and not a clean iron audio only on iron. I could get an Iron Low-Tone on some small gold bracelets and small foil, small child's gold rings, etc., that other brands provided me with a cleaner ferrous/non-ferrous split.
Reading this small portion of the manual just now also brings up others things to question. For example:
First is Tesoro's tried and tested ED120 discrimination. ... Yes, the ED-120 Disc. models are very tried and tested and proven. That's why three of my five Tesoro's have that Disc. circuitry because they have proven their abilities with it. HOWEVER ... the Golden Sabre Disc. circuitry isn't an ED-120 range of acceptance.
Offering 120° of discrimination range covering a broad spectrum of unwanted targets. ... I know this will confuse some people. Do you know what it means? Did the writer or editor know want what it implies? If you take a Bandido II µMAX and a Golden µMAX and increase the Discrimination of BOTH models to reject all targets up to and including screw caps, then BOTH models provide the same range covering "a broad spectrum of unwanted targets" so there is no difference between them. Most ED-120 Disc. models provide the same range of Discrimination and offer the same amount of acceptance [size=small](the upper 120° of the fill 180° range)[/size]. But the Golden [size=small]micro[/size]MAX is different because it uses more of an ED165 range of Discrimination.
That means, an ED-120 Disc. model, such as a Silver Sabre [size=small]micro[/size]MAX, is already rejecting almost all iron at the minimum Disc. setting, and only responding to the targets with a conductivity level in the upper 120° of the 180° acceptance range, while the Golden µMAX, with the Disc. set at minimum, is allowing the acceptance of more targets on the lower-conductive end, to include all foil targets and some iron targets due to it accepting more targets that fall in the upper ±165° portion of the 180° range of acceptance [size=small](which would be All Metals, both ferrous and non-ferrous)[/size].
In the end, the Golden µMAX performance is going to be very dependent upon your settings, the ground mineralization and iron mineral content of the site you search, and the target depth and orientation to the coil. I know I tried a few [size=small](3)[/size] Golden µMAX units in a variety of hunting environments from Oregon costal salt water beaches, to Easter Oregon Gold Mining Era camp sites, to Eastern Oregon and Utah Ghost Towns, to the beaches at Lake Havasu, Arizona. Probably 80% of the time, or more, the Golden µMAX provided me with just 3 functional tones and not 4, and I always had the Discrimination set at minimum. Also, I had a lot of copper cents and clad and silver dimes produce the 3rd Tone and not the higher-conductive 4th Tone.
Anyway, just some comments about the Golden µMAX, the Owner Manual with incorrect Disc. range description, and reasons why that models just never worked for me. I have several all-time favorite Tesoro models, and that one will never join my favored group. Best of success with yours for the areas where you'll use it.
Monte