Filters, When To Use High Pass?

[5900_XL-1]

I don't remember anyone discussing the high pass selections in filters. Do you ever use it, and why? martin

 

[Rob (IL)]

Page 52 of your manual.

A little more sensitive in areas free of external electrical interference.

 

[TheMarshall]

I don't remember anyone discussing the high pass selections in filters. Do you ever use it, and why? martin

****************************​

Use the higher filters reluctantly, for they will 'in general terms', reduce the apparent detectability of targets.

There are times when detection depth is limited by 'bad ground'', in which case the main criteria is 'limiting the effective loss.'

In some instances, increasing sweep speed to some optimum value, dependant on depth and target, will enhances the detection of an object.

In either of these cases, it will be beneficial to employ a 'higher' ground filter to offset the incurred ground effect.....normally by using 'High pass' ones.

If other factors introduce 'interference' besides the mineralisation effects, then a 'BAND-PASS' version may offer the better filtration.

The band-pass filter is more selective / restrictive on what signals it 'lets through' compared to the High Pass.....(Block low...pass all higher frequencies..possibly including 'interference'.)

There are problems incurred with offering 'brief' explanation's on such a complex subject, which may not carry the message well enough for some folk.

Please comment if a better explanation is required...........TheMarshall

 

[5900_XL-1]

Marshall,

That is information not precisely explained in the manual, which BTW is a very generic manual to actual users. I've never read where anyone has selected high pass, so it would be cool to have someone say "This is where I used high pass filters, because..." Like I say, the manual is shallow in many ways. I don't care if the best manual readers, who are not metal detectors read it. It takes people here with real life stories, to really explain it and make it clear. martin

 

[Neil in West Jersey]

n/t

 

[Larry (IL)]

The best and easiest way to learn about filters in your ground and swing speed is to try them. Click on one and try it for a while. You can read until you are blue in the face, but the best teacher is YOU.

 

[jbow]

I usually use 7.5 band or high but I don't really know why... sometimes I will use 10khz band or high and some times 5Khz band or high... I usually find a target and match the frequency to match my swing speed for the best audio... but there really doesn't seem to be that much difference. I usually run recovery delay around 50, sometimes 45... sometimes 60-80... and I figure all these things interact.
If I understood Rob correctly he said (via the manual) to use high pass when EMI is low and you will get more sensitivity. You are saying that high pass will reduce the detectability of targets?

I am a little konfused. So high pass is better if there is no EMI and band pass is better if there is higher mineralization? I assume if there is mineralization and EMI band pass will still be better...

as I said though... I cannot tell much difference. Of course the grouund at most sites around here is hard as a rock and full of actual rocks.. so the sink rate is really low most places. Still, there are those places with a higher sink rate and deeper targets but they are generally either plowed or have had fill dirt and are fertilized...

I wish someone would write a book. There have been rumors of a book since the V3 came out.. now we have the V3i and still no book... I guess to long time White's users it isn't such a problem but to those od us new to White's some things dont make sense because so many who explain things assume we all know the terminology used by White's... and that isn't so much of a problem on this particular subject, but in general. These forums do help though.


Thanks Marshall,

Julien

PS, I have a Marshall that was made in England!

 

[jbow]

n/t