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I did a quick recording of items I had going from a small nickel silver bead through a screw cap. Total of 20 items 6" away in both all metal mode and discrim mode with disc at min.

It is interesting how you can actually see the different sounds and how they have unique patterns. I plan on redoing the test when I can set up outside. There is a lot of emi here and my audio setup was not tuned so I couldn't hear the threshold through the computer even though it was pretty loud on the detector. The audio was also recorded really hot which I will correct next time.

Wonder if digital machines have just flat signals with no variation other than tone and volume? I can't record my Garrett as it has a proprietary audio jack.


All Metal Tejon.jpg

Disc min Tejon.jpg

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  • 1 year later...

Update on this subject. I did a new recording and it seems sensitivity really doesn't effect depth but rather a bit of detail to the audio itself. It also seems to have stereo output, might explain my last couple hunts I had set my headphones to mono and had some trouble telling targets apart. Thought I just lost my touch.

The Tejon seems to have a fixed gain. With that in mind I set the machine to 10 sensitivity on lowest disc. and recorded the following targets.

medium gold ring, us nickel, square tab, large platinum ring, pull tab, copper penny, silver ring, clad dime, clad quarter, silver half dollar. Targets passed over the coil at approx 6" away and approx same speed.

medium gold ring.jpg

us nickel.jpg

square tab.jpg

large platinum ring.jpg

pull tab.jpg

copper penny.jpg

925 silver ring.jpg

clad dime.jpg

clad quarter.jpg

silver half dollar.jpg

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Ya I saw that. My first post was with the stock concentric and had trouble recording the audio as it was clipping out on me. This was done with the 10x12 widescan.

Did forget to mention my swings over coil where right to left to right (rx to tx then back to rx). You can see how the machine has a different read on either side of the coil, guessing they boost the tx (high output transmitter HOT). I wish it did have a gain control. I'll be running the machine as sensitive as I can instead of the usual 7-10.

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May I ask what you used to record the audio and graph it like that? I'm looking to start a little project by making a "target id bible".  Have those images placed in a database or something and then when I'm hunting I could create a program that matches the tones to what I have in the database.  


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The Tejon has a standard 1/4 jack so i used that with an adapter to the 1/8" jack and plugged it into my computer to the microphone input. Used a free program called Audacity to record the waveforms.

Things that can vary those wave forms can be EMI, ground conditions, distance to target and swing speed so it may or may not be super accurate going from a house to the field. I just did this as a comparison of different objects to each other in the same environment with what ever varialbes that came with it other than distance and swing speed.

Those were also recorded in disc mode and is why the forms are shorter than all metal mode that would be unfiltered.

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