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).
Since you received no responses before, I will respond, however, I will qualify this as being a secondhand response from my turntable dealer. (I am somewhat of a newbie to analog, so I will definitely defer to the more knowledgable people on this site.)
I purchased a used Basis 1400 TT, and it came with a brand new nonefelt extreme mat ($25 new, I believe), still in the package. It arrived via UPS and I brought the entire package to Brian at The Analog Room in San Jose, CA to have him set it up, as I was purchasing my cartridge from him. (His reputation proceeds him as THE expert in analog in our part of the country). When I showed him the mat, he threw it back in the box and said not to use it, that it would sound better without it.
Since I have a RB 300 tonearm, which does not have an easy VTA adjustment, I have never experimented wtih it based on his recommendation. I trust Brian, and it does sound fantastic without it. (In fact, I am going to be giving the new mat to a friend (he loved the sound of my system so much, he too bought a TT), so he can exchange it with his felt mat which came with his TT).
These are my thoughts on the matter.
Good luck in your research!
I think that what mat works best will vary from table to table and installation to installation. This has to do with the various damping characteristics of the tables suspension, the quality of the bearing / noise transmitted from the drive assembly itself, how well the table is supported, how susceptible the table is to both air and floor-borne vibrations, etc... In effect, one could change mats and use them as "band-aids" to fix other problems that the table / arm combo suffered from. The end result might be some type of colouration ( reduced dynamics, softer transients, etc... ) that is more pleasant to listen to than the original components.

As a side note, Kurt mentions a very important aspect that many people overlook. The differences in thickness from one mat to the next can play havoc with VTA, etc... Unless one resets VTA after changing a mat, they are not so much hearing what the mat has to offer, but what the differences in VTA change. As such, for consistent performance and sake of even comparisons, you would need to adjust VTA for each mat and then listen. Sean
I think Sean is on point, there is no one answer to which mat material is best. What works for one TT may not work for another. With that being said, in the hay-day of vinyl, a lot of scientific research was done on turntables and their components. Kenwood's testing suggested sonic improvement as the platter mats progressed from rubber, to felt, glass,and ceramic mats. the use of an outer record weight and spindle mounted record weight increased the sonic performance greatly. If you accept this line of testing, the ridged mats should work the best. I use a currently use graphite mat with an inner and outsdie record weight, but intend to test a carbon fiber mat in the next week. I have also used the latest harmonix record mat with excellent results.

I have used a ringmat on a Rega P3, a Basis 2500, and an LP12. Why these little, skinny cork rings should work is beyond me, but I don't like the sound with the alternatives as well. I do find that I can tell the accuracy of my settings by how obvious a positive difference it makes.

A nice bonus is that I don't experience static cling, requiring me to peel the felt pad of the record.
My initial experience with a Ringmat was very poor. Come to find out that the better the isolation of the turntable itself, the less "synergistic" the Ringmat will be with it. As such, i would not recommend the use of a Ringmat ( or similar device ) with a table that offers good to excellent isolation. Such devices will probably work better with a table / installation that is more susceptible to outside interference. In effect, the damping or "give" that such a platter mat offers becomes part of the suspension and can help to make up for a lack of isolation from both air and floor-borne vibrations. Tables that offer excellent isolation from outside influences will typically work better with a more rigid platter mat.

That's why i mentioned the variables involved with the different types of suspension and support structure that one is using. You have to look at the big picture, not just what works in one specific situation. I learned the hard way i.e. by spending money and taking a step backwards in performance. Sean
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.....
Uh oh. Another opened can of worms.

TWL, and others, thanks.

By the way, anyone hear the AVID Volvare. My retailer loves it. But with an arm and cart it would be minimum $5500 new. Would it really better a Nottingham Interspace with a Dynavector Karat? Its almost 3k more.
Richard, I have heard that Avid table only once so I cannot give great detail without blowing smoke (though that doesn't stop quite a number on this board). I am not partial to the sprung subchassis tables, in general, at that price point. I will say that the Avid Volvare WILL definitely best the Interspace by a significant margin. $3K better? That I will leave to the opinion of others.
Richard, I responded to you personally with respect to the Mystic Mat.

Boston Audio makes a mat that is cut from a solid cylinder of graphite and ground/polished/sealed to extremely close tolerances. I wish I had a couple extra hundred to throw around to try one out, myself. Someone asked about it awhile back and got no response. I checked out the link and then did some networking and I have received reports of good success with these on 'Nots, Michels, and VPI. Would like to hear of other reports.
Nottingham lists a Spacedeck "heavy kit" that's a carbon-based "mat" for $1000; basically, it's the 3/4 " top-platter from a Nott' Hyperspace. That has always suggested to me that carbon/graphite would be a good avenue to check out--the Mystic Mat (or the Boston mat) seem to be more real-world priced than the official Nottingham mat.
How about this one: