I set my threshold with the gain at about 9 o'clock(pulse at factory preset) turn the threshold so you have to realy strain your hearing and concentrate to hear it, leave it there. Now turn up the gain to about
2-3 o'clock and your ready to go it will crackle and plop but a true target will be easily heard, try to keep the coil as level as possible to cut down any falsing especially at the end of the swing. if the noise really bothers you you can turn down the gain, doing extensive tests on numerous targets i have found that not a lot of depth is lost if you keep the threshold real low, if you up the threshold the slight rise of a target will be lost in the background an missed on the lower gain settings but it is almost as deep. This works in my area but you will have to experiment in yours