I was wondering if there is any correlation between the gain # and depth. Meaning...is it a sliding scale of sound where it is always the same depth distinction, with a tonal change based on gain #......Or, does the depth change based on gain #. Ex. if you are detecting and want to be alerted to targets say deeper than 5 would there be an appropriate gain # for this.......Or, would you only be changing the tonal sound on all targets based on depth?