Hey guys . Picked up an old garrett ads 3 on the cheap... read the manual but theyre a fairly complicated bit of kit and ive never tried detecting before.. any hints from old timers there isnt much info available on the net. Should i be setting my audio threshold in all metal to hear a constant tone or just under..i know it works ive excavated some rusty old crap already..but its complicated. Any help would be appreciated should i hunt in all metal. I found vlf disc more effective at picking up targets. Cheers