ANSWER: You can use Silent Search on when designing or installing a program. Or on site detecting, but it will not improve the detectors capabilities in any way by
turning Silent Search on.
I recommend leave off, as there is a slight trade off in depth with it on, it is far better to lower the Threshold Tone instead to an acceptable level, and use Audio Discrim Mode. When on, the Eagle Spectrums Audio Discrim Mode is on by default. On the XLT always leave Audio Discrim on. On the DFX Silent Search over rides Audio Discrim Mode And Mixed Mode Audio, whether they are on or off.
QUESTION: When do I use Mixed Mode Audio on? Will I need to adjust anything else, how does
ANSWER: Use on for any site where it is difficult to get a decent swing of the loop, like Maze stubble, very long grass, very rough ploughed that you can hardly walk
on, iron contaminated Roman sites.
When beach detecting any hot spots like Black sand, gullies, or rock pools. Use off for sites with lots of modern rubbish. Or for general detecting where you are able to use your normal sweep of the loop. Because when the loop is moving at a reasonable rate, the Audio Discrim section is in operation anyway, gaining very little benefit from the all Metal Mode Section. Yes when you turn Mixed Mode Audio on make sure Preamp Gain is set no higher than 2 or 3, then increase D C Sensitivity as high as possible, while still maintaining a steady threshold tone,
Mixed Mode Audio is
a Dual Mode Facility, when the loop is moving; the Audio Discrim mode is in operation. When the loop is moved very slowly or Stationary the all Metal Mode is in operation.
It works the same in the Eagle Spectrum, XLT and the DFX Detectors giving a high tone for all metal targets as the loop passes over them - it plays a melody of tones if any metal target is large or near the surface. When the loop is stationary over a metal target, or as the loop passes over a metal target when searching very slowly, this is when the all Metal Mode section comes into operation, giving a low tone for all metal targets. When a target is located give two to three sharp 15 to 20 centimetre long sweeps of the loop, to bring Audio and Visual Discrim into operation for target identification. Mixed Mode Audio will Work with Audio Discrim Off on the DFX. Recommend always use Audio Discrim On at the same time on both the XLT and the DFX. It is on by default when Mixed Mode Audio is selected on the Eagle Spectrum.