Why a threshold based all-metal mode can be important....

[CWRelichunter]

I finally found a graphic illustration to show why a threshold based all-metal mode is import to <b>ME</b>, and some other metal detectorists. (I found it in the operations manual from one of Minelabs detectors.)

I hope this will help show the importance (perceived or otherwise) of having a threshold control knob while detecting in a threshold based all-metal mode. In this type of all-metal mode there is not going to be any kind of tone ID or variations of tone, but only one single tone that responds to any targets detected by rising in audio threshold volume.

<i><b>However</i></b>, some of the zero discrimination modes out there in some detectors MAY have a threshold tone, but the ATR (audio target response) is usually a separate signal that BEEPs and rises above the constant threshold that remains steady, and this is a different subject entirely. Confusion usually begins at this point.

I realize many of you reading this may indeed be confused and require more explanation, but this post is <b>not intended</b> to teach or instruct those not familiar with all-metal modes. This post is simply to press the point of how important the threshold based all-metal mode is to <u>SOME</u> of us out there in the metal detecting community. Those of you that hunt in all-metal mode will see the point I am making here.

J in VA
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[Cody]

The first silent search detector I used was a Fisher and there was no threshold hum. The discrimination was called chirp discrimination due to all the little pops and snaps it made. A solution was to have no audible threshold. User complained about no threshold so Fisher put and audible tone that was actually a false threshold. We could hear a tone but when a target was hit it was obvious the tone for a threshold was not in fact a threshold.

A detector that only has a tone

 

[Digger]

The information you posted explains the logic of threshold based detectors. But I don't see where your chart and post have much to do with your original post of the X-Terra not having what you consider to be a true all-metal mode. Threshold tone or silent search, in relation to all-metal or zero discrimination, is like comparing apples and oranges. I have silent search detectors and I have threshold based detectors. I can run in all-metal or discrimination mode and still have a threshold on some. (Whties XL Pro) Some of my silent search detectors have an all-metal mode as well as a fully adjustable discrimination mode. (Minelab Advantage) I agree that having a threshold tone is a great tool for seasoned hunters. I have places I could still use my old Garrett BFO. As I have stated on numerous occassions, I can learn as much about a target by the diminishing audio volume as I can by an increasing volume. But I fail to see a correlation between the all-metal vs zero discrimination string you started and the post you just made here concerning thresholds. Maybe I just missed something. ????HH Randy

 

[tony (Orlando FL)]

I am old school on this. I can turn off all disc and have an all metal setup, but its still a MOTION BASED all metal mode. There seems to be a play on words that isn't what we want or expected to be meant by 'all metal'.

Someone that is buying a new tector and wants a Non-motion based All Metal mode with active threshold on it needs to ask or be sure they are getting what they expect is all there is to it.

On the other hand, the detector advertising could also be more specific in their ads stating motion or non-motion modes, with active threshold or not.

Many times on the newer models, the threshold setting is simply for adjusting the volume of the pinpoint threshold level to a bare minimum only.

I, as always, could be wrong, but think this is what the complaints are about the zero disc mode vs all metal mode. Its knowing with confidence what the manufacturer means by all metal mode and what you will be getting.

Tony

 

[JW]

a separate cicuit for all metal non-motion, which is a true all metal mode.

 

[CWRelichunter]

However,

Although I certainly agree NON-motion goes deeper (no argument at all), this was never intented to be a discussion about motion vs non-motion. I believe people went astray when I had mentioned the PINPOINT mode in a separate paragraph of my original post, and they assumed that I thought it was exactly the same as a SEARCH mode motion based all-metal mode. Instead of writing two posts, I simply merged several thoughts into ONE post.

Anyway, You are 100% correct when you said "knowing with confidence what the manufacturer means by all metal mode and what you will be getting". That's the whole discussion here. If there are some folks who want to discuss the history of metal detecting on these forums and run off on tangents that's fine, but your last paragraph sums it all up pretty good.

Here is my last point that I will make on this forum. Just to set the record straight, and if these history buffs want to argue back and forth about how wrong I am I don't mind at all, but for the record the order of depth capabilites are generally speaking as follows. I will list these from weakest to deepest:

1) Zero-Disc motion modes. With or without the "fake" audible thresholds.

2) Threshold based, motion all-metal modes with autotuning or SAT.

3) Threshold based, Non-motion all metal modes without autotuning or SAT. (A perfect example is the Whites 6000 pro XL or 5900 series. Anyone who has used those models know that GEB NORM goes deepest, then GEB SAT, then DISC mode.)

J in VA (later.....)

 

[Ralph Bryant]

Manufacturer specs are only important if you understand their meaning in the first place.

Just a thought.

 

[Digger]

I don't believe that any currently manufactured single frequency detector can provide discrimination characteristics or visual target ID without coil motion. We know that the X-Terra is a silent search single frequency detector. Being silent search means that it don't need a threshold adjustment. As well, the X-Terra does not have SAT (self adjusting threshold). The pinpoint mode can be non-motion, all-metal, because it does not provide discrimination or target ID. Since the X-Terra is silent search, no threshold tone, and by definition all single freq detectors with discrimination characteristics must have motion to provide visual target ID, it stands to reason that the all-metal button will not provide a "non-motion" all-metal mode? Not if it is going to provide visual target ID and discrimination. Even if that discrimination level allows all metals.

In my opinion, the difference between non-motion all-metal AND motion based "zero discrimination" is not in the type of targets that can be detected as much as it is in the motion required to detect and identify those targets. But, that is just my opinion. HH Randy

 

[tony (Orlando FL)]

Bottom line is its very important to know what you want when buying a new tector and ....to be able to ask all the right questions before plopping all your hard found $$s down.

In addition to this, we need to be able to understand what the company or dealer is telling us while reading their ads or even while we are at a tector shop in person.

We need to be able to tell if the person explaining the answer really understands the question and really knows the answer by asking same question in different words. I am positive the dealer wants to get the answer to the question back to you as accurately as possible.

Lets face it, every dealer or manufacturer rep isn't necessarily going be an old timer with the same field and equipment experiences as you. Some may not even be into detecting at all and may only repeat what they heard or have read.

When spending $$s it is important to know what you are buying, so its wise to have a list of questions at hand and make sure they all get answered.

Seeing/trying the unit in person should help eliminate a good chunk of the questions that we may have. The machine will answer your questions themselves. IF an in-person demo is not possible, we need to sharpen our on-line, on-phone and e-mail skills to ask the right questions and understand the answers.

In the end, , it still requires knowledge at both ends of the conversation to make for a successful purchase.

I'm done.