[steve f]

The title says it all. What are you favorite mats? Do you like a certain mat for suspended tables? A different one for mass loaded tables? How about for metal or acrylic? There are a lot of choices out there.

steve

[S Clark]

Of the limited # that I've heard, Herbie's mats were the best... best mid detail, clearest bass, and lively.

[Letitroll98]

A homemade Spot Mat.  Google search brings the proper thread right up.  The sound is clean and clear, layers of mud lifted.  Material can be cork, construction paper, leather, plastic, or a mix of these.  I used all cork and cork dots on construction paper, with all cork preferred.

[neobop]

I've had the most success with mats that try to match the mechanical impedance of the record.  In the old days, it was the Goldmund mat made of methacrylate, and the Sota Supermat made of a Delrin type acrylic.  These materials are similar and the hardness can be varied.  The exact formula was kept a trade secret.
More recently Boston Mat (carbon), now discontinued, and Applied Fidelity (acetyl) had the same goal.  Funk Firm's Achromat (carbon cardboard?) purports to do the same and uses bubble like tunnels in the material to prevent vibrations from re-entering the record.  Acrylic platters attempt to do the same thing, with varying success.

From an interview with Pierre Lurne designer of high end tables:
"From the Minimum turntable in 1979, through the second turntable which I designed for Audioanalyse in 1981 and now to the Audiomeca J1, I used the same concept of mechanics. I'll begin with the platter. I agree with other designers that methacrylate is the best material for a mat, and the shape of the platter is the same as the Minimum, which is to say that it is a little concave: it slopes from the outer rim to the center at an angle of 0.30$d. I decided on this form from a statistical survey of a large collection of records. There are actually two sheets of methacrylate, either side of a solid, 8mm-thick piece of lead, giving a total mass of 8kg.

"This construction is something very special. If you know the velocities of vibration in methacrylic and in lead, you can calculate when the vibration is reflected back to the stylus. First, the vibration induced in the record from the stylus tracking the groove goes through the record into the methacrylate, then to the lead, and so on. Each time the vibration is transmitted from one material to another, there is reflection and transmission, and the time taken for each reflection to return to the stylus can be calculated. You need not have all these delayed signals reach the cartridge at the same time. You then get the same effect as with the acoustics of a room with square dimensions—one big resonance. This is no good, and in addition, when a large reflected vibration reaches the stylus, the tracking is instantaneously different. But if you take care of the spacing in time of these delayed reflections—do you understand the concept of the 'Gold Number?'—then neither the music nor the tracking is affected, not at the beginning of the record or at the end.

"We use lead because it almost behaves as a 'magic material.' It has high mass, it has good damping with low-Q resonances, and it has a very low speed of vibration. If vibrations enter the lead center of the platter, they leave considerably later, much lower in amplitude."

Right now I'm trying a 3mm Achromat with a lead sheet underneath.  The lead is about 1mm or so thick and weighs a little over 500g (1 lb).  By itself the 3mm Achromat left something to be desired IMO.  I also have an old mat made of expanded foam and I seemed to get good results with it on the bottom, the lead on top, and the Achromat above that.  It was getting a bit too thick and the edges tended to lift so I started at the middle of the LP side. 

Now I want to cast some lead mats of different thickness.  A mat that weighs 2 or 3 lbs. can be accommodated by some tables. 
neo

http://www.stereophile.com/interviews/pierre_lurne_audiomecas_turntable_designer/

[Quiet Earth]

Right now, my favorite mat is the Boston Audio Mat 1 combined with a Stillpoints Ultra Lp Isolator (on my Nottingham SpaceDeck).

I have the supplied "foam" mat for my SpaceDeck which is very good, but perhaps a little too polite. I have gone back and forth so many times between the foam mat and the Boston Audio mat trying to decide which sound signature is correct. The very rigid Boston Audio mat gives me a very lively and spirited sound which made me revisit my cartridge alignment until I got it just right. That is a good thing in my opinion. The foam mat is much more forgiving, with a polite and easy going sound that is dull in comparison. I may never have gotten everything dialed in just right if I didn't venture beyond the foam mat.

Highly recommended, even if you don't like the sound of it. It's a great mat and a great set up tool.

[Devil Doc]

No Mat! Although my turntable manufacturer provides one they believe the deck sounds better nude; the record directly on the aluminum. I believe them.

Doc