Tone Hunting Tip

[earthmansurfer]

I think this is for those newer to the V3i (like me!). I had never hunted with a tone machine before and when I first got the V3i I was using one low tone for iron (5) and sequentially incrementing tones from 0 (@161 or so) to 95. I think the book calls this "shifted". Now, the very interesting thing is that when you sweep across a target just one time you often get more than one tone. Apparently, the V3i processes the signal continually (not just averaging it) and reports more than one tone on the swing. Now, this sometimes flute like sound might be annoying to some people. But there is an interesting thing about it. See, if you really listen you can often pick up bigger jumps in the tone. (Remember, the human ear is much more sensitive to tonal changes than volume changes.) A tonal jump of just one or two isn't much, but if a VDI is jumpy you will hear that in the tone as well. You will see that in the spectragraph too. I don't think spectragraph settings affect the audio (I run consistency on 8 and a Fade rate of 3) but they sure aid in getting more from my spectragraph.

Anyway, on shallower targets I notice that if the tone is really jumpy it's often not a good target (no trash where I hunt, that might change things). A bottlecap can be an extreme example of this, a rolling like sound depending on it's condition. (I don't run BCR btw.) The other day I dug an antique metal bottle like cover of some type and it really "fluted" all over the place. I thought "That sounds terrible and is probably trash." but I dug it to see what it was anyway - to verify what I heard. But I'm a coin hunter so to me it was trash. The spectragraph reflects this "bad target" with more smearing as well - or a wider range (with my above settings) but it is cleared quite quickly for the next swing (and I think it builds it as well). Again, don't give too much importance to the sounds and data as a coin gets deeper. Though, even on deeper coins I have noticed the spectragraph lines up quite often and there is not much smear, depending on the iron.

If you hunt with your audio in blocks (e.g. - 1 tone for a range of VDI's) I think by definition you are averaging the audio information in a sense and perhaps getting less information. Not saying this is bad as there is still loads of information in the sounds. I still have to compare here.


It's a bit hard to write what I've experienced but I definitely see me understanding the sounds and putting it together with the other data the machine is giving me.

I hope this was of some use to some of you guys. I've had nice machines in the past but this one takes the cake with all the information you get.

Any related findings here from any of you guys?

Thanks,
EMS

 

[squirrel1]

I totally agree with you. Funny thing is I purchased an e-trac 4.5 months after I purchased my V3i. I was very dissapointed with my V3i. After receiving my e-trac I went to the same sites I had hunted with the v3i and found numerous coins some deep, some shallow-some clad, an a lot of silver; especially dimes. So I started giving some thought on how I missed the coins. I actually remember hitting one of the buffalo nickels with my V3i, but I didn't dig. The e-trac gave me a solid ID so I dug it-the V3i didn't. To make a long story short, I feel I do better with the V3i if I assign the highest tone possible for VDI numbers 35-94 and
then maybe a substantially lower number tone to everything else. This makes the V3i sound more like my e-trac and if I get the super high tone it will cause me to stop and investigate. It gets rid of the pinball machine sound that's very hard on the ears and brain.

 

[earthmansurfer]

I totally agree with you. Funny thing is I purchased an e-trac 4.5 months after I purchased my V3i. I was very dissapointed with my V3i. After receiving my e-trac I went to the same sites I had hunted with the v3i and found numerous coins some deep, some shallow-some clad, an a lot of silver; especially dimes. So I started giving some thought on how I missed the coins. I actually remember hitting one of the buffalo nickels with my V3i, but I didn't dig. The e-trac gave me a solid ID so I dug it-the V3i didn't. To make a long story short, I feel I do better with the V3i if I assign the highest tone possible for VDI numbers 35-94 and
then maybe a substantially lower number tone to everything else. This makes the V3i sound more like my e-trac and if I get the super high tone it will cause me to stop and investigate. It gets rid of the pinball machine sound that's very hard on the ears and brain.

Actually, the "flute sound" does sound like a E-Trac when it's programmed that way. I think you got what I said backwards. Each VDI going up from 0 has a tone of one more than the one before it. I am not putting in one tone for 10 VDI's or the like. For example, VDI 0 = tone 161, VDI 1 = 162, VDI 2 = 163 and so on all the way to VDI 95. I think the shifted tones (one tone for each VDI) can communicate more information about the target, at least if it's shallow. This is just a hypothesis as I need to play more with it.

The downside is potential audio fatigue or just plain losing the target if there is trash around it. I hunt mostly in iron, not around that much trash, though I have used this to ID trash as well.

It appears the V3i uses continuous signal processing and not sampled signal processing for this shifted tone to function the way it does. It if is sampled it's reporting the samples quite quickly. Rob or Larry, do you have any idea about the processing?

 

[Rob (IL)]

It appears the V3i uses continuous signal processing and not sampled signal processing for this shifted tone to function the way it does. It if is sampled it's reporting the samples quite quickly. Rob or Larry, do you have any idea about the processing?


As the signal that is being processed decays, if another signal is picked up that is stronger the decaying signal the instrument should sound off on that target so it will be detected. However if the second signal is weaker than the decaying signal then this target will be ignored due to the long recovery delay.
This was from my recovery post. ROB

 

[earthmansurfer]

Rob - You are talking about another signal. I'm talking about the same target. For example, I can uncover one target yet on a swing across I get multiple tones (which sounds flute like).
Your description is of the discrimination circuitry and I'm familiar with that. (And it's an important point when hunting small targets or around larger pieces of trash - you would probably want to lower the recovery delay edit - I shouldn't say discrimination circuitry but point taken). But that does not relate to the signal processing being continuous or sampled.

Here is a good definition of what I'm talking about and if you understand how your detector operates it is of significant help as you can see:

Continuous Processing
The detector processes a continuous signal response throughout the duration of the sweep of the
searchcoil over the target. All characteristics of the target are audibly communicated to the user.
Continuous processing gives a good feel for the size, depth, and shape of the target. Continuous
processing is preferred, for example, for relic hunting, especially in plowed or rocky ground.
Sampled Processing
Sampling takes a snapshot of the signal at its strongest point. This compromises the feel of a
continuous response, but provides for more accurate target identification. Sampling also
eliminates confusion caused by changes in tones during the sweep over the target. Sampling
is preferred, for example, when coinshooting in areas where there is aluminum trash.

 

[Rob (IL)]

In discriminate search mode, the audio is adjusted for each sample of data that comes in until it gets to the peak. The audio then stays at the peak value until the signal has decayed via recovery delay and stuff. I don't think the spectragraph is updating on the down slope. The VDI display is based on the peak value (and on the way up on the signal, each value is a new peak value). All metal is all continuous. ROB

 

[earthmansurfer]

In discriminate search mode, the audio is adjusted for each sample of data that comes in until it gets to the peak. The audio then stays at the peak value until the signal has decayed via recovery delay and stuff. I don't think the spectragraph is updating on the down slope. The VDI display is based on the peak value (and on the way up on the signal, each value is a new peak value). All metal is all continuous. ROB

That is a GREAT description Rob. Now it makes sense. The V is sampling data as it approaches and leaves the coin and giving sound feedback as it does so. So, if you have one tone for each VID you can hear this process happening. This can be valuable to those with sensitive ears. On the other hand, I imagine one block of tones (as mentioned earlier) also has it's own advantages as you still hear information in the tone (clarity, breakup, etc).

By observing the spectragraph, I think you are correct that it doesn't sample on the down slope. (Things seem to "tail" in one direction.)

Thanks so much for that description Rob, a lot just clicked for me

 

[Low-Boy/LCPM]

That would be too much sound for me to deal with... I like a four tone detector set up on the V3i from -5 to +14 a low tone say 100 for chains and small gold then a high tone 250 for VDI 15-29 and then a lower tone for say 150 for 30-60 and then a tone of 200 for VDI 61-69 and then 250 for VDI 70-94..I am still working on that..I have found that on the LTD that one tone gives the most info we call it mono tone but I like 2F tone where I hear the iron as a grunt and the relics and coins as a mono tone. The LTD works the best this way. But the V3i is a different beast that is why after reading on this forum, I have nothing disc out but have -95 through -6 at a 0 tone. And have + 95 at 0 tone..

 

[Larry (IL)]

That is what is so nice about being able to assign tones to each of the 191 VDI numbers.