Combined audio allows the user to hear different target signals, based on either ferrous or conductive properties. You set the ferrous line (horizontal line) where you want ferrous targets to provide the audio response. If, for example, you set it at 21, then any target with a ferrous reading of 21 or higher (larger number), you will hear the audio tone that you program for ferrous targets. On the other hand, if the target has a ferrous reading that is less than 21, the target response will be based on it's conductive properties. And in Combined audio, you have four "bins" representing conductive groups. With conductive numbers running from 01 - 50, you simply move the lines to represent different target groups, then assign a tone for each group. For example, you could set bin one with the lines at 01 and 14. Any target with a ferrous value less than 21, and a conductive value of 14 or less would "fall" into this bin and provide the audio tone you associated with it via programming. Bin two, for example, could represent targets between 15 and 28. Bin three could represent targets from 29 - 40. And bin four could be the remainder of conductive targets, with CO values of 41 - 50. So with the numbers used in these examples, if you passed over a target with a FE value of 12 and a CO value of 44, it would provide a conductive tone that you assigned to conductive bin space four. If you passed over a target that read 11/22, it would provide a tone based on conductive bin two. If the target read 24/29, it would give you the tone you programmed for the ferrous value (below the horizontal line). Again, the user can resize and assign tones to each target group (bin). For the folks who enjoyed hunting in Two Tone Ferrous on their E-TRACs, this is like TTF on steroids in that you can adjust the FE line, and break down the CO targets into four separate groups. HH Randy