Vibration-dampening effect of rubber bumper
The right cue vibrates from end to end and that bit of dampening on the end of the cue can indeed change harmonics a little. Depends on what you like and how sensitive you are as to if it is a good thing or bad. I'm thinking about putting delrin bumpers on my cues, for no good reason at all.
Hu
Folks:
Hu hits on a point here. There's actually a product out on the market called "LimbSaver X-1" that is a concentrically-ringed special rubber bumper that one can install in place of the original bumper:
http://poolndarts.com/p-5470-Limbsaver-X-Cue-Stick-Stabilizer/
I was originally skeptical of these things ("how can a rubber bumper at the one end of the cue affect the hit that's happening on the opposite end??"), but after understanding a bit of vibration harmonics, I happened upon an opportunity to get one of these cheap to try it out. I installed one of these on a very, very old Players cue (circa late 1980s -- probably when they were still very well-made) I had that'd lost its original rubber bumper. (It'd worked its way out and fell out on its own one day -- never could find it.)
I gotta tell ya, folks, this thing does make a difference. The difference ranges from very subtle to noticeable -- depending on how hard you hit the cue ball. Originally, this particular cue had a very noticeable vibrating "ponk" sound when the cue ball was hit hard. (The sound was nice -- very woody, but the vibration is what I'm emphasizing here.) There wasn't anything loose inside the cue, it just resonated pretty noticeably, especially if I had to hit a shot hard to stun the cue ball for position. I could actually feel the vibration way back in my grip hand. I was pleasantly surprised at the difference the LimbSaver made -- the cue still had its nice woody "ponk" sound, but the vibration was gone, even with a very hard stun shot. For this particular cue, the LimbSaver was a match made in heaven.
Anyway, that's a take on the rubber bumper from a different end of the spectrum -- shock absorption from shots, vs. tapping the cue's butt on the floor.
Hope this is helpful!
-Sean