Mat Material...............

What have you found to be the most effective mat on your TT? I was surprised noone answered my query on carbon fiber mats. Carbon fiber? Construction paper? Felt? Uranium? Titanium? Nothing?

Some of these mats can get pricy. $200 for a carbon fiber from (I don't remember).
My isolation is quite good. I'm using a Nottingham Interspace table with Dynavector Karat cartridge, Bright Star Audio Rack of Gibralter, and a homemade sandbox similar to a Big Rock.

Do you think a Mystic Mat (I hear it's recommended by Nottingham) could be a good choice? It's a carbon fiber make-up.
A record mat can perform several functions. Most of these functions are to improve the performance of a platter with inherent design flaws. If the platter is properly designed(which many aren't), then a mat should not be used or needed. If there is a design flaw, then a mat can possibly provide the compensation for that flaw, depending upon how severe the flaw is. For example, a mat could be used to dampen resonances or vibrations, or improve impedance coupling to the platter, or be used as a VTA spacer, or any number of things. How well( or badly) the mat works on a given table, will directly be the result of what mat is chosen for what platter application and how it addresses the platter flaw in question.

In a very well designed high-end turntable, there is rarely a use for a mat, and you don't see them very often on those kinds of tables. In the lower price range tables, where cost-cutting measures cause some compromises in design, then the platter mats may have some application.
So, TWL, do you think a Notttingham Interspace is low end enough to benefit from a mat? I probably think so. Do you think tweaking vibration compromises the use of a mat? I recognize it's a "check it and find out situation." I'm just trying to avoid a needless expense if it does nothing or worse.

By the way, do you think replacing a fiberboard plinth with maple is worth the effort?
Richardmr, I'd recommend that you contact Audiogon member 4yanx about this. He has quite a bit of listening experience with Nottinghams and variations and tweaks. I think he could give a more accurate recommendation than I could.

Some people like the maple, and in general I think that a good hardwood like maple would be less harsh than HDF. I think it would be worth a try. I think that the HDF platter is probably a little harsh too, but the SpaceMat is supposed to take care of that problem.

What kind of sonic change are you seeking, or feel the need to address?
Hard platter upon stylus exerting pressure, which is modulated by the groove, becomes microvibration that hits the hard platter surface, and bounces back. The 'microscopic chatter' will add a haze of noise to the music, and also affects all the 'audiophile qualities' (soundstage, tonality, extension, etc). To ride the chattering vibration, the cartridge/tonearm has suspension and damping, but this occurs quite far away from the source of the chattering. Imagine that most of the effect are 2nd order mathematically - so even the stylus suspension that is one cantilever away, the Young's module of the cantilever comes to play, as can be proven by fancy hollowed-boron, diamond-coated, and other science to inmprove rigidity.

The ringing platter (metal, glass) solution rather than dealing with the microvibration, they try to conduct away the vibration energy to the plinth (ground), in the process, they introduce some rining artifact. Having precision bearing and platter faciliate the grouding effect.

The hard surface, where some comments as lacking in PRAT - could be the result that energy modulated by the prior music passage becomes the residue to the current music passage (I am currently involved with designing amplifier with 5Mhz feedback vs. conventional 10ms feedback, and it's a revealation.. but that's another story...)

Felt is a material that avoids the 2 hard surface bouncing energy back/forth, but the problems are the slip in horizontal plane and vertical variation accorss the wool pile.

Then we come up with the clamp - more interesting, it exerts higher pressure near the spindle and the edge of the record will elevate, plus, by having variation in pressure, the reflection of energy between vinyl and hard platter is now uneven.

Should you worry about the above? Perhaps not, as the VTA is probably off, or the VTF is not optimal, and the tonearm azimuth is probably mounted off, and the cable has more oxide that creates a lot of thermal noise.

Add to the fact that the records playe on the turntable are cut 10-100x more inaccurate than the precision platter/bearing.....