Isolation device under Ayre CX-7e?

what is paper coaster, by the way?

If you use cardas wood block, would you put it on top of MDF shelf or something else?

A paper coaster is a small round piece of absorbent paper on which a drinking glass can be placed.
MDF is usually not as good sounding as wood, depending on the footer. But, with Cardas/Ayre myrtle wood cuboids the ultimate sound varies with the positioning under the component, as well as the underlying flat surface material, so you could start with MDF if it is already in your possession.
I have experimented in different systems with the Cardas myrtle wood cuboids ("block" is not a fancy word when advertising this item) on different pieces of wood furniture, on maple slabs, on granite slabs, on formica surfaced plywood, and even between two stacked components (one should never admit this) with satisfactory results, because there are so many variables.
These cuboids can be placed on top of component cabinets to damp the component, and change the sound in a subtle way, which can be better or worse, so you just have to be flexible with this sort of inexpensive, helpful "tweak".
Sometimes, there is no precise "right or wrong" answer to a question which makes it possible for you to decide for yourself, and not have to feel you did something "wrong".

Last night, i tried several tweaks and here is what i did:
1> Ayre cx-7e on Tenderfoot which is on top of maple wood. Sounds ok.
2> The same as item 1 above , but i also put 4 grungebuster dots (http://herbiesaudiolab.home.att.net/gb.htm) under the maple wood. The soundstage is really big, but not smooth, especially vocal. I get tired of listening after 5 min. Also, bass is louder but boomy.

3> I put the integrated amp on top of maple wood which is on top of Grungebuster dots. CDP is on Tenderfoot which rests on the shelf (MDF). The sound is smooth as i like, but the soundstage is a bit smaller. Basically , the whole thing with this setup is coherent and balanced.

I guess i will try Myrtle block to see what happen. I don't know much about the theory behind all of this ,but isolating the integrated amp somehow makes improvement.

I had the Arye Cx 7 e home for tre days, after a short while i got tired too, I moved it around, on the carpet, on sorbortane feet, diffent cables, power leed, at last I gave it back to the dealer. Thinks the problem is that the transport is cheap (computer transport), its alu that the case is made off, No absorbing of noise (look inside). Use my Stax elektrostatic earphone, the problem whas here to, It whas the player not my set up, use power leed and cables, and diffent feet too. Dit not help at all.

Kindy regarts

I used to own Arcam FMJ CD33. Honestly, the arcam sounds more musical and smooth, or tube like. Then I switched to Ayre CX-7e. Ayre is more details, but not the way i really like. However, the CX-7e mates very well with my Totem Forrest speaker.

By the way, i put 3 myrtle blocks under CX-7e. Bass is tighter and tighter. Mid range is smoother, but the high is kind of edgy...or , if not saying harsh sometime.

I guess it may be affected by the way i put my integrated amp on top of maple platform which rests on the MDF shelf.

I know there are many factors may affect the sound and keep tweakling is getting tired...