ctx 3030, threshold and annoying low frequency "bips"

[Konstantin]

Hello,

I recently bought ctx 3030 and I run into a behavior I cannot explain.

I hear very annoying spontaneous low frequency "bip" sounds. It seems they appear when threshold sound and target sound overlap.

Here you can find an example (1st video): https://picasaweb.google.com/103094990424097799437/3030?authkey=Gv1sRgCOac15O_sr_VQQ#
You can hear these low freq "bips" (especially in the middle of the video, sorry for the quality)

My setting there are (plz see link above):

- 50 conductive: 700Hz-930Hz
- Volume Gain: 20
- Threshold Level: 20
- Volume Limit: 19
- Threshold pitch: 1

As you can see there should be no any low frequency sounds at all because of 700Hz-930Hz setting.

Actually the "bips" appear with any other settings. The only way to get rid of them (almost, they become very silent) is to set "Volume Gain" to 1 and "Threshold Level" to 1. Or to set Profile mask to "reject all". "Accept all" mask gains the "bips" appearance.

I understand that my test slightly crazy because there is lot of electricity noise etc in the room but it actually helps to reproduce the behavior.
On-field testing also shows the "bips" but they appear rarely mostly on "dirty" spots.

So the question is: Is it a feature or an issue?

These "bips" are very annoying because they are much louder than threshold sound level - almost as loud as target signals.

Thank you,

Konstantin

P.S. The "bips" sound almost exactly as the sound when you press any button.

 

[earthmansurfer]

It looks like you are running it in the house and it is falsing like mad. When mine falses in the house (at 20 or more sensitivity), it sounds like that.

Try running it lower or more preferably outside and away from EMI.

Albert

 

[Big Boys Hobbies]

It looks like you are running it in the house and it is falsing like mad. When mine falses in the house (at 20 or more sensitivity), it sounds like that.

Try running it lower or more preferably outside and away from EMI.

Albert

Agreed.

 

[Konstantin]

OK, I'll do more out-door tests...

But the question was why did it produce these low frequency beepes when sound settings was for hi freq targets only...
Even if EMI makes it mad in a room - there should be only crazy high tone bips and no any low tone ones..

Thank you

 

[Digger]

Try using Noise Cancel. If it doesn't clear it up, change the NC channel manually until you find one that is not as succeptible to (what sounds to me to be) electrical interference. HH Randy

 

[Konstantin]

I understand that there is definitely something that is interfering with my detector. I made sensitivity high enough to make my question easily reproducible.

The question was not why it is interfering (high tone sounds) but why did low tones appear?
They should not appear because I set my 50 conductive to 700Hz-930Hz range. And all the fake "target" signals were in high tones and this makes sense for me. But what are the loud low tone "bips" ?

So with those settings I should hear:
1. 700-930Hz targets who include "fake" EMI signals
2. very silent low freq threshold sound

And I can hear 1 and 2 but there are also low tone loud "bips" that I cannot explain and that make no sense because of 700-930Hz setting. Even if it is false EMI signals - they must "bip" in 700-930Hz range...

Thank you for you help

P.S. I just "moved" to 3030 from x-terra 705 and I wanna understand what it is trying to "tell" me. And these low level "bips" are messing me up....

 

[Larry (IL)]

EMI causes strange things to happen and as soon as you move away from the EMI source, I'm sure you will not have the low "bips" to worry about.

 

[Konstantin]

Hi Guys

Here is my outdoor test (no any EMI, couple coins on the ground, auto noise cancel): https://picasaweb.google.com/103094990424097799437/3030?authkey=Gv1sRgCOac15O_sr_VQQ#5772645920402735890 (sorry for the quality)

The low frequency "bips" are there...

Could someone else set

- 50 conductive
- tones: 700-930Hz
- threshold, volume and gain on 20+
- open mask

and try it out? Will you have only high frequency target "bips" (as expected) or these spontaneous low level bips also (grrrr)?

Thank you in advance!

 

[Digger]

Around the 19 second mark, you'll hear two of them in a "rapid fire" sequence. If you look at the display when those blips are firing, the display indicates two targets, making me wonder if the low tone is your loud Threshold resetting after each target? I'd suggest you lower the volume of your threshold to a barely audible tone and try slowing down your sweep speed. Worth a shot! JMHO HH Randy

 

[Konstantin]

Sweep speed makes no difference.

The only way to make them almost silent is to set "Threshold" to 1 and "Gain" to 5 or less... But I can hear "Threshold" tone only when it is 10+ ;(

I also noticed that the low freq "bips" appear mostly when it makes transition: target -> threshold tone... If it is a feature I cannot find it useful (at least so far) - having only target tones and threshold would make more sense.

I hope someone will test his device with my settings (this should not take more that couple minutes)...

Thank you!

 

[Konstantin]

Just tried "Response" = "Pitch hold" - works like magic!

No any crazy distracting low level beeps at all regardless of "Gain" and "Threshold" settings!

 

[hershey1]

What is the hz. setting below your FE line. Sounds like that may be where your low tone blips may be coming from? Just a thought.

 

[Konstantin]

I tried it on open mask - the same

 

[IDXMonster]

Threshold resetting. Notice the low frequency "bips" are the same pitch in tone as your threshold. If you want to test this,try changing your threshold tone ALOT and see if the "bips" also change to that pitch in tone.
When hunting DEEP coins sometimes it will make the same noise with a very quick high tone of the coin in between two of the bips. Some refer to it as a "thunk" sound...it is regarded as a GOOD thing to me,especially if you make it repeat!
Glad you found a response setting that will work for you...happy hunting!

 

[bklein]

I don't really understand the motivation here. If you have EMI all bets are off if Noise Cancel doesn't work on it. You can pick the best NC channel (it may take several seconds to "take"), back the Sensitivity down, but then you don't detect targets very well. I have this EMI problem in my front yard but not the back. If you are stuck with the EMI and want to run tests or something you might try the 6" coil instead of larger. I bet you could edit the discrimination page to "full reject" (all grey) and still hear the EMI. Please try it and let me know.

 

[IDXMonster]

After actually WATCHING the video and not going strictly by description of problem,I wholeheartedly agree with bklein. The detector responds to EMI as if it were actually seeing a million targets,this is indicated by your screen and it lighting up everywhere randomly. The smaller the receiver,the less the EMI,hence the suggestion of a smaller coil. I seriously doubt I would hunt a site with the kind of EMI in the video if I couldn't NC and get find of it,unless I knew I could turn the Sens WAY down and still achieve hitting desirable shallow targets.
Don't run your machine indoors...

 

[BigTony]

What if you lowered the threshold below normal range?

 

[bklein]

I tried my front yard with an all grey screen and you then only hear the random low pitches. Since the hits are random, discrimination not the right route to reduce them.
Detection of coins still works as expected with the EMI and no disc. Just use auto NC or manually go through them for what you prefer. The number will affect the detectability of some targets especially if in ferrous mode.
I guess it is reasonable to ask what is unique about the target ID when the low tones sound - I notice those sometimes on iron or bobby pin targets with no EMI in play. Often you get accompanying red triangles displayed.

 

[denny]

. Ask minelab directly. EMI will make detector act crazy. Just use noise cancel. If you still want to know why it acts the way it did contact minelab.
Hello,

I recently bought ctx 3030 and I run into a behavior I cannot explain.

I hear very annoying spontaneous low frequency "bip" sounds. It seems they appear when threshold sound and target sound overlap.

Here you can find an example (1st video): https://picasaweb.google.com/103094990424097799437/3030?authkey=Gv1sRgCOac15O_sr_VQQ#
You can hear these low freq "bips" (especially in the middle of the video, sorry for the quality)

My setting there are (plz see link above):

- 50 conductive: 700Hz-930Hz
- Volume Gain: 20
- Threshold Level: 20
- Volume Limit: 19
- Threshold pitch: 1

As you can see there should be no any low frequency sounds at all because of 700Hz-930Hz setting.

Actually the "bips" appear with any other settings. The only way to get rid of them (almost, they become very silent) is to set "Volume Gain" to 1 and "Threshold Level" to 1. Or to set Profile mask to "reject all". "Accept all" mask gains the "bips" appearance.

I understand that my test slightly crazy because there is lot of electricity noise etc in the room but it actually helps to reproduce the behavior.
On-field testing also shows the "bips" but they appear rarely mostly on "dirty" spots.

So the question is: Is it a feature or an issue?

These "bips" are very annoying because they are much louder than threshold sound level - almost as loud as target signals.

Thank you,

Konstantin

P.S. The "bips" sound almost exactly as the sound when you press any button.