As a Pro Staff Team Member for Techsonic Industries, (Humminbird/Zercom) I have had the opportunity to use some of the best electronics available to help me locate fish. Many times finding the fish is harder than catching the fish, especially when conditions are such that the bass suspend. I personally don't know anyone that likes bass suspended well off the bottom. These are nearly impossible to catch, but you can learn to catch other bass by finding suspended bass.
Bass suspend for any number of reasons, water color, light penetration, barometric pressure, thermocline and even boat traffic pressure. Bass may be suspended at fifteen feet over thirty feet of water, the numbers don't really matter. The thing is, is to locate the suspended bass. If they are at fifteen feet, use your depth finder and cruise the river or lake looking for fifteen feet of water. Find water at that depth with bait fish and or cover and there will be fish there, and they will be catchable. The bass are there because that is where they are most comfortable on that day. I can't count the times this trick has worked for me when fishing conditions were very tough. Find the depth the bass are seeking, then fish your favorite baits until you find the bait of the day. I don't spend a lot of time fishing actual suspended bass, but I do let them show me the most likely depths to fish. Now, go get em' and throw one back for me.