Here's my .02 worth on this subject. I have a couple of Shakespere 5.0 Micro graphite rods that Fat Albert shortened to about 4'6" that I bought at Walmart for about $14.95. Shortening these rods has stiffend them up just a little bit and to me has increased the sensitivity. But I have a theory on Crappie fishing and on how they either bite or how we sense when they do. Again, my definition of a theory is - "a supposition based on ignorance of the subject matter."
When you "feel" a crappie thump a jig, it is my theory that the fish is trying to eject the lure. Most of the time when I feel this and hook the fish, the jig is usually hanging on the lips or just barely hanging on the lips. When I "see" a crappie take a jig, either by watching the line jump or move sideways just a little bit and set the hook, 99% of the time, the jig is set deeply into the roof of the mouth and I usually have to use needle nose pliers to remove the jig without harming the crappie. You hardly ever lose a fish like this at the boat, but if you feel a crappie "bite" the lure, I miss fish trying to swing them into the boat a lot of times. The exception to this rule is during the spawn or the rare times when the crappie are unusually aggresive. They hit the jig with a rush then and you do feel it about the same time that you see the line twitch. Or you are fishing straight down to deep or suspending fish and just "dead" baiting the lure. You will feel the bite then before you see the line move. That just makes sense.
Use light line hi-vis yellow Mr Crappie (4 or 6 pound test), small jigs (I use 1/32 oz 95% of the time regardless of depth), plastic lures (panfish assassins, stingers, tubes, curly tail grubs). Learn the slingshot method of casting the lure. Not only for shooting docks, but a great way to control your lure in wind as you can shoot it low under the wind most times. By all means, be a line watcher and learn how to count. Crappie are very picky at times and will only be caught at a certain depth. Fish 1 foot above or below the level they are suspending on and you won't even know they are there. Find the magic depth and wear them out until they move. Crappie move vertically more than people realize.
Use your electronics. If you have a side scanning unit, that is a great tool for locating crappie in open water. Liveliner can attest to this. I turn the transducer on my trolling motor mount 90 degrees so that it scans sideways and is pointed in the direction of the arrow on top of my trolling motor. That way I know where to avoid casting and where to cast if I am in open water. If you are fishing shoreline cover, most of the crappie will be behind you anyway. Get a side scanner and you will find that I'm telling you the truth.
I perhaps have gotten off the subject a little bit, but I hope that this helps you guys and gals who love to crappie fish and wish that they could catch more. You can catch them all year. They are not just a spring time fish. emoBigsmile emoGeezer