Silent Threshold on the GT

[akille68]

Hello Folks,
Is it true that using silent search and turning the threshold up to a slight humm appears to make the machine a little more sensitive?
All the best.
Ale

 

[Nauti]

Hi there,i've read that too somewhere and never really thought much about it.However,after reading your post i thought i'd try a little test.The test i did was a simple air test on a small coin.Firstly i tried the test with the machine in normal threshold mode and noted the maximum distance the sov would pick it up with a good clear signal.I then tried it in silent search and turned the threshold up so i could just hear it.This is what i found-
1.The sov seemed to give a louder response to the coin at the same distance
2.I could get about half an inch better depth with the silent search/threshold method.
It seems to me that there may be some truth to this method after all......would any other sov owners like to try this test and post their results.....it may answer the question more accurately if there were a good number of test results.Good post Ale.

 

[Critterhunter]

Great little test. I've been curious about this as well so I think I'll give it a go and post my results. Maybe with silent search the threshold is being automaticly boosted up by a certain amount so it's past the "silent" wall (buffer/filter/whatever you want to call it) and the target can easily be heard. If that's the case then perhaps by using silent search and then adjusting the threshold just high enough to hear the machine is still boosting the threshold by a certain percentage when it passes over a target, causing it to now be even louder that it would be without silent search being used. Hope you know what I mean here...Let's say threshold is normaly at a 5 on a scale of 1 to 10 in threshold mode, with anything 4 and below being silent. Silent search drops it to say a 2 or 3 but will then boost it to a 6 or 7 when you pass over a target to make sure you hear it. I guess it might function somewhat like an audio boost if it does work that way.

 

[akille68]

Many thanx for Your replys, guys.
I think that it works like a Tesoro Vaquero or Cibola supertuning.
Also it looks have a faster recovery speed in silent search, maybe because it has no more the variable threshold pitch.
I will do some tests in the next days.
Take r.

 

[Critterhunter]

Yea, people say (and I think even Minelab in the manual?) that you can pick up the sweep speed in silent search. I'm prefer silent search machines but with the GT's threshold holding the tone of the last target I now prefer using it's threshold mode. Some machines designed to run in silent search do not lose any depth compared to running in threshold. Machines not designed to run in silent search can lose depth if you crank it down to where you can't hear it. The silent search mode on the GT might be an interesting compromise when it's not used for what it's intended for.

 

[midalake]

I will test on some on my deep target hits on the beach tomorrow.

Dave

 

[Nauti]

Just done a little test on the sweep speed in silent search theory.Basically the test was the usual one....nail next to a coin,sweep over the nail and see how close you can place the coin to the nail and still get a signal.I tried the sov in silent and threshold and to be honest there was no difference at all.I don't think increasing the sov sweep speed is a good idea,even with silent search on....not on my machine anyway.

 

[kered]

What i can't fathom out is how you tell the recovery speed is faster, if you can't hear the threshold how can you tell its recovered, maybe its too early in the morning

 

[Nauti]

It does not matter that you cannot hear the threshold.The test shows how fast the machine resets after it's discrim circuitry has come into play.I've seen people do this test with two or more good objects.....virtually any detector will recover at speed with this test due to the fact that the machine does not have to use it's discrim circuitry.In the case of the sov,when i did the test in silent and threshold mode the coin was picked up at exactly the same distance from the nail showing that the speed of recovery had not changed.I'm not really a great believer in these tests though because although they do give an accurate indication of a detectors reset speed,i believe that when a target is in the ground other factors come into play such as soil conditions and conductivity of trash and good items.I'm finding this more and more with th sov because although it has a slow reset speed i'm finding i can pull good targets from quite heavy trash.

 

[Critterhunter]

Ummmm.....You guys are confusing two seperate things here. There is a distinct difference between sweep speed and recovery speed.

Sweep speed is how fast or slow you can sweep the machine without it losing depth, becoming eratic, or mis-identifying targets. For instance, ever linger over a target too slowly with your sweep on some machines and find the ID and audio degrade because of the lack of faster motion? Some Whites machines are touchy to too slow of a sweep speed. Slow down too much over the target and it's perfect ID now turns to a trashy one. By the same token, the GT is prone to nulling, unstabile operation, or phantom signals if you increase it's sweep speed too much.

Recovery speed is how fast the unit resets between targets. Silent search is NOT supposed to increase recovery speed but it is said to allow you to increase your sweep speed somewhat on the GT. I think even the manual says that.

Recovery speed and sweep speed are two different subjects completely.

 

[Nauti]

Sorry Critterhunter...i mean't recovery speed and not sweep speed.I was replying to akille68 because he said that it "looks to have a faster recovery speed in silent search"......i just did the test to show if this was the case.My mistake....well spotted.

 

[Critterhunter]

No need to apologize. I've been known to mix them both up in terminoligy myself once in a while...

 

[midalake]

I work the beach yesterday and on several of my whisper targets hunting in all metal on Threshold and in pinpoint. I switched over to silent search and both pinpoint and fixed mode. I thought the target might have been slightly enhanced in Threshold, but the sound was a little different with how the elctronics sound. I really like how the electronics churps in pinpoint. I am not sure the other one will be as easy to pick out. I will test a little more on whispers. Also if I have a few deep hits in an area I will work them out and go slow in the other mode.

Dave

 

[Critterhunter]

Good info. Keep us informed. It's an interesting subject that deserves some testing and exploration. Never even though about it's potential advantages in All Metal. I always thought silent search only worked in discrimination since I haven' toyed with that yet.

 

[Neil]

I work the beach yesterday and on several of my whisper targets hunting in all metal on Threshold and in pinpoint. I switched over to silent search and both pinpoint and fixed mode. I thought the target might have been slightly enhanced in Threshold, but the sound was a little different with how the elctronics sound. I really like how the electronics churps in pinpoint. I am not sure the other one will be as easy to pick out. I will test a little more on whispers. Also if I have a few deep hits in an area I will work them out and go slow in the other mode.

Dave

pinpoint has the really defined signal whereas in fixed/tracking mode youll get more of the broad sound, closer to disc mode. make sure and move the coil around in tracking mode first so it can set itself to that location and then go to fixed mode otherwise your going right to your pre determined setting.
I always liked testing this way also, the deep whispers can tell you alot as you play with the controls to get the signal stronger/cleaner.
also try backing off your sensitivty and see if you loose the whispers/if they stay the same or if they get louder. then try turning it up and seeing what you come up with.