Personally I prefer a setting of 8 as iron just is just a more shrieky sound for lack of better words and as far as wheatie or indian head audio is just a hair lower and sticks right out for me. Bryce prefers a setting of 10 and heck whatever works as we all have different hearing and many have trained ears from hours in the field and well some guys just never figure out the audio whether it be inexperience or perhaps their tonal hearing abilities. Experiment guys and once you find what works for you stick with it and thats why Minelab gives us so many settings. I am sure many excell with the Explorer series and if I made a post to have one post their individual settings you would find many variances between individuals and honestly no stock answer only what works for a particuiar individual in his neck of the woods.