Nevada Brian Posted January 13, 2017 Share Posted January 13, 2017 On 1/7/2017 at 11:16 PM, Chet said: Hello Chet, thank you for taking the time to perform this test. Would I be correct in saying that the nickel is giving off a high/low sound based on the oscilloscope display or is there a double signal? Brian. 1 Link to comment Share on other sites More sharing options...
flakmagnet Posted January 13, 2017 Share Posted January 13, 2017 Great post Chet. Interesting and educational. Thank you. 1 Link to comment Share on other sites More sharing options...
Chet Posted January 14, 2017 Author Share Posted January 14, 2017 4 hours ago, Nevada Brian said: Hello Chet, thank you for taking the time to perform this test. Would I be correct in saying that the nickel is giving off a high/low sound based on the oscilloscope display or is there a double signal? Brian. Some hear different sounds on different targets under different conditions. I have a difficult time with recognizing musical notes. The only musical instrument that I play well is the phonograph. Some complex functions are occurring to produce the unique and pleasing sounds of Minelab Pulse Induction detectors. So a high/low sound has two characteristics to consider; a change in volume and a change in tone. I will try to explain what is happening in target sounds. On the oscilloscope display; the vertical waveform envelope starting on the left is rising in volume to the top of the display; then decreasing in volume until near the center of the display. At this time the nickel is passing over the center of the coil. The sound volume is nearly off at this point. Then the sound increases and decreases again across the other side of the coil but at a lower volume than was heard on the left side of the coil. At the same time another function is occurring; if you look closely at the sound envelope it is made up of software programmed digital pulses that are being generated in a manner that generates a change in audio frequency tone as the volume is changing. The lower volume pulses at the beginning of the left side of the envelope are tightly spaced together which is a high frequency tone. The pulses spread apart as the volume increases which is changing to a lower frequency tone. At the top of the display the tone has reached its lowest tone frequency. Then the pulses become closer together as the volume decreases reaching a high frequency tone near the center of the display. The lower volume sound envelope on the right side of the display starts with a high tone and increases even higher in tone as the volume increases then decreases in tone as the volume decreases. There are many variables that effect target response sounds from Minelab detectors. Some are the size and shape, the distance from the coil, soil mineralization, ferrous, nonferrous, and speed of sweeping. During the test there was high Electromagnetic Interference from neighborhood computers, TVs and electric lines. The GPZ 7000 detector settings used to reduce the effects of EMI were as follows; High Yield, Difficult, Sensitivity 5, Frequency 60, Volume 6, Target Volume 12, Threshold 1, Audio Smoothing OFF, the coil was ferrite balanced on a cement floor with no rebar. The Frequency, Threshold, Sensitivity and Volume settings had the greatest effect on mitigating the EMI. The nickel was attached to the bottom of 16 ounce bottle of water. The bottle was suspended by a seven foot cord to function as a pendulum. In order to further mitigate EMI the nickel was within two inches of the coil on each swing of the pendulum. I had to capture many swings of the pendulum to find a waveform that was not clobbered by EMI. This same nickel buried in the field with a quiet environment and normal detector settings will generate a different waveform and an overall different target sound. There are some sample sounds at;http://www.victorianseekersclub.org.au/detector-sounds The sound of this setup was similar to the first sample ‘Inverted’ Gold Signal. Have a good day, Chet 6 Link to comment Share on other sites More sharing options...
Buffalochip Posted January 14, 2017 Share Posted January 14, 2017 Great job Chet! Very interesting! Have you heard of a release date? I want one! 1 Link to comment Share on other sites More sharing options...
Steve Herschbach Posted January 14, 2017 Share Posted January 14, 2017 The Minelab Pro-Sonic is already in dealer hands in Australia and should be available from U.S. dealers any time now. 1 Link to comment Share on other sites More sharing options...
Au4Gold2 Posted January 14, 2017 Share Posted January 14, 2017 Top Post ! 1 Link to comment Share on other sites More sharing options...
Randy Lunn Posted January 14, 2017 Share Posted January 14, 2017 Well done Chet! Great analysis and description of what it meant. Thx! 1 Link to comment Share on other sites More sharing options...
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