How on earth does this work?

[Hoop27]

We were finishing off our budget monster field (pics to come!) and we were having an issue with too much vibration at midfield, after trying a couple things I recalled something about a strip of duct tape across the over active area.

Well we tried it and watched our player just go from end to end with no issues. I'll be honest I was shocked and dumbfounded that it worked.

However I can't wrap it around my brain how this actually works and it's driving me nuts! Can someone who is much smarter than I am (brighter than a house cat would qualify) explain why this works before I go mad?