Record mats, VTA, clamps and my ears

Not knowing what your cartridge's specified VTA is, or what VTAs you might actually be running with the three mats in question, I'm going to punt on the angle issue. I will venture to say, however, that unless the stylus is a fairly radical line-contact, spade-shaped configuration, I'd guess that the mat differences are responsible for most of the audible changes, as long as the set-up got the VTA essentially correct to begin with.

It's not surprising that you would hear the largest degree of improvement from using the clamp with the least good-sounding of the mats; that is the one that will need help the most. The better mats will get you more of the way there without the aid of a clamp, while still benefitting from its use.

I'm not familiar with your particular model of clamp, but if it's typical, with a diameter that's just a little smaller than the record's label, and a clamping surface profile that is lowest around the perimeter and higher towards the center spindle, then you may need to shim up the mat surface center about the spindle, with a compressible washer placed over the spindle, under the record. Effectively raising the central mat surface slightly above the level that's underneath the record's grooved portion, creates a small downward dishing of the record when the clamp is applied, which ensures near-complete contact of the record with the mat in the area between the lead-in and lead-out grooves. The washer should not be larger than about 3/4" in diameter and about 1/8" thick, and is commonly made of felt, although sorbothane or cork can work too.

However, if the mat surface is not entirely flat, but rather is contoured to be depressed in the area under the record label, then you may have to add another, non-compressible washer, made of plastic, hard rubber, cardboard, or metal, below the soft one, with the right thickness to just compensate for the mat's center depression and bring the bottom surface of the upper compressible washer to the same height as the main mat surface. You'll have to push down on the clamp before tightening in order to get the desired downward dish of the record, but be careful about trying this with certain older vintage records made from styrene or shellac, which will not flex like modern vinyl, and can break. Taking these measures should prevent the clamp from pushing the record's label into the soft mat and raising up around the edge, thereby achieving proper coupling of the record to the mat and platter.

Forget about record mats - Sean is absolutely right. They tend to decouple the LP from the platter and hence you lose all the mass loading that most good turntables provide (i.e. they make the platter huge and heavy) Decoupling usually thins out the bass, smears detail, etc.

What you want is the LP flat on the platter so that it is well coupled to the platter and hence the entire mass of the rig. I generally don't like threaded record clamps but weights which rest on the LP are fine. There are some good commercially available options or you can rig up your own using a clever and inexpensive technique one of my employees invented.

Take a leaded crystal candle holder, stick a candle in it. Cut the candle off such that the wax is flush with the top of the candle stick. Remove the wick. Invert the candle holder and put it onto the spindle such that the spindle is inserted into the wax but the leaded crystal is in contact with the record label.

Bingo you have a cheap and very effective record weight which does improve the quality of your analog playback. Again, what you want to achieve is optimal mass loading and coupling and this is why adding mass to the record helps.

Bear in mind that you may or may not need to restrobe your turntable motor after adding significant mass to the platter with the aforementioned weight.

Just to confuse you further, and to disagree totally with Sean, I have found the Ringmat far superior to three clamps I tried, including the carbon fiber Black Diamond Racing clamp. This is with a VPI TNT which has ALWAYS been clamped until I tried the Ringmat. The sound is rich, dynamic, focused, airy (but certainly not "thin") and has less surface noise than with the clamps. But your inability to adjust VTA must be considered. And you have to overcome the feeling that the Ringmat is an overpriced piece of paper and cork. Good luck in your quest, Dave

While it may not seem like it, i always encourage "contrasting points of view". That is why i said "let the fireworks begin" : ) If everybody felt the same way or did the same things, there would be no need for forums like this as we could not learn from each other.

To respond directly to Dave's ( Dopogue ) comments, my findings are based on the following observations. By posting these, i hope to clarify why i've made the statements that i did and help some of you better understand why / how i arrived at these conclusions:

1) you MIGHT reduce surface noise on discs using a non-supportive mat due to the fact that the record is not uniformly flat or evenly supported. The stylus is actually riding higher in the groove and is therefore not picking up the "gunk" that is ground down into the groove. While this might seem like an initial benefit, read on.

2) The problem with this is that you now have accelerated side wall wear on the discs and have increased uneven wear on the stylus since it is no longer centered down into the groove.

3) Since the stylus is no longer centered and riding as deeply in the groove as it should be, you now have less distinct left / right imagery. Bass impact is also reduced since the stylus is no longer fully modulated by the entire depth of the groove. If you have a pivoted arm, anti-skating is also affected in a negative manner.

4) The reduction in direct deep groove contact with the stylus reduces dynamic range. Since the stylus is not "pushed" or "modulated" as hard on louder passages since it is riding only the upper surface of the groove, there is less variance from the quiet to loud passages and dynamic range is reduced.

5) Since the stylus is no longer seated firmly and deeply in the groove, tracking ability is reduced. In order to compensate for this, one must increase the downward pressure ( tracking force ) applied to the cartridge. This can be verified if you have test LP's set up to measure the tracking ability of an arm / cartridge combo. In severe situations, the stylus will literally be thrown out of the groove. Needless to say, this is not good and is not only offers audible proof that this type of mat is not beneficial to performance, it offers visible proof.

6) Besides all of the above, a non-supportive platter mat that does not fully support the record and somewhat "floats it on a cushion of air" or "decouples it from the platter" allows the disc to be influenced by air-born vibratrions to a much greater degree. This can lead to increased amounts of acoustic feedback and lower resolution. This is especially true if you like to listen at higher volumes or have speakers that are capable of room shaking bass. The records can actually "micro-vibrate" to the beat of the music being produced at volume by the loudspeakers as they move great amounts of air. This in turn can modulate the stylus within the groove which results in less accurate transfer of information from disc to stylus. As such, all of the isolation or coupling that one has done to minimize TT chassis induced vibration goes out the window as you've increased the problem of "micro-vibration" directly at the record to stylus interface. This results in a greater amount of "haze" and loss of true detail while adding artificial artifacts to what you are hearing. Granted, the artifacts sound "musical" in many aspects as they are directly derived from the beat of the music that is helping to modulatate the stylus within the groove.

As one can probably gather from all of the above, i'm pretty opinionated about this and most any subject that you throw at me : )

Honestly though, i've taken steps to try and miminize all of the above problems and that is why / how i found out what i now know. This knowledge is based on first hand experience with a lot of testing involved. Being a technician by trade, i want to know and understand why something works / doesn't work, so i've tried to do things in a manner that helps me break things down to the point that i can better understand the situation.

As such, i've ended up using a very heavy chassis on the turntable to minimize the impact that external vibration might have on it. The platter and arm are suspended so as to further isolate any vibration that might make it through the already mass loaded TT chassis. The platter is heavy to increase flywheel effect, i.e. minimize speed variations due to taking advantage of having the momentum of high mass already spinning, the platter mat is fully supporting of the disc, the disc is anchored at the spindle via a clamp to increase coupling to the platter and minimize air-borne vibrations, the outer edge is secured in place via a vacuum platter to minimize the effects of warpage while also increasing coupling to the platter and the arms that i use are linear tracking in design to minimize tracking error and keep the stylus as centered within the groove as is possible. These arms also allow adjustable VTA "on the fly" so as to be able to compensate for the slight differences in vinyl thickness.

While i know that there are many different thoughts on the subject, this is what i've found to work best. Obviously, others might have different points of view. As such, i'd love to hear them and why they have those thoughts. I'm never against trying to learn or comparing notes : ) Sean
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Sean, I would have agreed with you totally -- and did for a long time. Then a friend convinced me to actually try a Ringmat. Back and forth, clamps to Ringmat (adjusting VTA with my JMW arm) and it ultimately became all too obvious. The Ringmat ruled. Like they say, YMMV. Cheers