CD player vibration from CD's

"Ddd1, Did you use a different Denon CDP of the same model and get different results? Or did you change players completely?"

The Denon was a DVD player. The players/transports that the same CDs didn't vibrate were different makes altogether. (ie. Simaudio Moon CD-1, CAL Delta, a couple expensive Sony universal players).

The Cd spins so fast, and the twist in the central area so tiny, you would not be able to see it. The biggest flaw in transport technology is that the CD is held only at the inner 2mm or so of the entire disc. So that central area can be off by only a few hundreths of a millimeter, and it will vibrate, especially if the disc is also very slightly off balance.
Like I mentioned, The one disc player that had a solution to this was the Pioneer Elite "Stable Platter" where the entire disc was supported, and the disc placed into the player upside down on a CD sized turntable.
I wonder why no other manufacturers ever used that?
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For some of the problem to be an individual players fault also makes sense, as the typical magnet clamp is pretty flimsy, and might have a manufacturing error that makes it more likely to not seat correctly. If this is the problem, opening the top up and checking the little top puck might help. The usual way it is in there the top clamp is held in a plastic holder, that only loosely/approximately lines up the spinning motor and the upper clamp. You can watch it load with the top off and see how it clamps on some of the vibrating discs. Perhaps all you need to do is push/bend the plastic holder of the top puck down a fraction of a millimeter. (I have done this)

I'm not so sure the problem is discs that are a bit off-centered. I once had a Yamaha S1500 player that would do this vibrating on occasion. But when I bought a Pioneer DV-79AVi the same discs played perfectly.
My opinion: a design flaw in the Yamaha or just piss-poor tracking ability.

the millenium carbon fiber mat reduced ad eliminated vibration on my friend's transport.

it is sold by aaimports. you can mention my name when you call brian. my name is roy harris. i own one.

I noticed a similar vibration on my PC's DVD drive, may be a clamping mechanism, don't know for sure.

I have a CEC top load transport which I use a Herbies Grungebuster adhesive mat on the bottom of the CEC puck for damping.

A De Mat (Van Art Speak) rubber and carbon fiber impregnated mat is also placed on top of the CD to very great effect, but I would not recommend this one for tray loading transports or players, they could jam.