Record mats, VTA, clamps and my ears

I've got a Thorens TD 316 with ClearAudio Arum Beta+. I've been experimenting with the original mat, a slightly thicker Audioquest Sorbothane mat, and a thinner Ringmat. I have dutifully ignored reading too much about VTA because my 'table doesn't support adjusting VTA.

The Sorbothane sounds better than the stock. Highs are the same, but the bass is less muddy. The Ringmat has a similar improvement in the bass, but there is more high end air. There is also very slightly more high frequency tics. But the problem is that some recordings sound thin. Airy, sure. But thin.

The turntable was set up using the original mat by a respected area tech. Not the very best high end guy--I would have been out another $200 had I used him. (The joys of the big city). Still, I'm confident my tech did a creditable job.

So I'm wondering how much of the differences I'm hearing are due to the change in angle of the stylus in the groove due to the different mat heights, and how much is due to the quality of the interaction between the 'table and the mat.
Are my findings consistent with advanced stylus angle theory? Should I have been paying attention in class when Sam T. told us everything I should already know?

Also, being The CheapSkate, I have a "The Original Pod Disclamp." Got it for twenny bucks on eBay. Anybody ever heard of this animal? Alas, I have questions. The Pod Disclamp worked best with the original mat insofar as the original mat is the stiffest. This is important as there is a depression around the spindle, so it physically possible to push the center of the record near the spindle down far enough so that the perimeter of the record raises up. No matter--even with the needle going up and down, things SOUND better that way! Arrgh! What does this mean? Must I now pay $2000 for a Final Tool just so I can own a 'table that follows the basic laws of physics?

Anyway, I try to apply just enough clamping force so the record is somewhat damped, yet not contorted.

The clamps effectiveness is reduced with the corresponding lack of stiffness of the mat. At least that's what my wife keeps telling me. So the clamp works best with the original mat, second best with the Audioquest Sorbothane, and third best (but still an improvement) with the Ringmat.

Hopefully, my confusion hasn't dulled your enthusiasm over providing me with my much lacked and sorely needed guidance.

I remain--

The Cheapskate
My experiene is that you want the record anchored, fully supported and as flat as possible. As such, your ears are telling you the truth and you are striding down the "most correct" path for vinyl reproduction.

Mats that offer limited support, such as the ringmat, tend to reduce the solidity of image, minimize bass impact and over-all warmth, increase ringing, suffer from increased artificial high frequency artifacts, etc... They are just plain "junk" in my book. Some take the increase in ringing / high frequency artifacts as an increase in detail and liveliness and think that it is a good thing. This is usually the case when they have an overly warm or "dead" vinyl rig or an arm / table / cartridge combo that is not optimized.

Obviously, this is strictly my point of view and it is worth every penny that you paid for it. Let the fireworks begin : ) Sean
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.
Not familar with your deck, but both the mat material/construction and it's thickness (due to changing VTA) will alter the sound.

I do not consider myself to be a cheapskate (a potlicker yes, but never a cheapskate), and coming from this standpoint you still have a couple of DIY mats to experiement with.

Try one mat made from "wool" felt (fabric stores sell 12" squares for $1-$2). Also, try one made from cork (thin sheets are available @ Home and Art stores. If the cork is in a roll it will need to be pressed flat for a few weeks before you cut the mat from it.

Depending on the overall thickness you could also try combining the two materials (flip the mat over to see which side sounds best up).

In general (in regard to VTA) the thicker the mat the fuller the sound and the thinner the mat the lighter/brighter the sound. When the tail end of a cartridge is lowered it will produce more bass and when the tail end is raised this will accent the HF's. The trick is to achieve a proper balance between the two and I have rarely been completely satisfied with a cartridge that has been set to the manufacturer's VTA specs (a little trial and error adjustment always seems to help).

Never owned a TT without VTA adjustment, but I just leave mine as is and use a thinner felt mat for thicker LP's (takes a few seconds to swap mats).
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.
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
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
No problem Dave. I'm glad that you found something that worked for you and gave you the results that you were looking for. I had tried the Ringmat on one of my previous tables with a pivoted arm and did not like the results. As such, i have never given them second thoughts and had moved on.

Is it possible that the added mass of the clamp that you were using or the manner in which the clamp was applied could have contributed a negative aspect to the TT being used ? I have never used a VPI but have seen the internals of one courtesy of United Package Smashers ( UPS ). To me, the table was of lighter construction and lacking mass, therefore making it more susceptible to both air-borne and floor-borne vibration. On top of this, the suspsension did not appear well suited to adding much additional mass to the platter. If the springs were already soft / and or not properly adjusted and you added additional mass to the platter, you might have increased the coupling from the TT chassis to the platter. If that were the case, going to a lower mass platter mat and removing the clamp might make all the difference in the world. Keep in mind that i am not critiquing your choice in gear or how it was set up, only commenting on the possible reasons why we might have observed such different results.

Obviously, others may have different points of view and experiences and i'd be glad to hear from them also. Sean
No, the VPI TNT is a very heavy TT (the platter alone must weigh 10 lbs) and is not "supposed " to benefit from a Ringmat. That's why I was so surprised.
Dave, i can see what you mean about these tables being pretty heavy. Thanks for helping me to realize that. I checked things out at Audio Advisor after reading your post and all of the VPI's there appear to be pretty stout. I'll have to ask my friend what model VPI it was that UPS obliterated. Sean
VPI's platters at the upper end of the product line are at least 20 pounds or more (acrylic / lead / cork combo) & yes I've been told that they are reported to work best with the record very closely coupled to the platter. Mine (a MK4 with a TNT bearing & platter) is supposedly that way. I'm not going to claim firsthand experience here, but the guy that I bought it from has. He had experimented extensively with mats & clamps, ending up with a paper thin "analog survival kit" mat & the Black Diamond clamp. Not wanting to 'reinvent the wheel' I've never tried anything else, but after the above read-through I'm tempted to begin experimenting all over again. Not that I'm unhappy with the rig as-is, in fact quite the contrary. Sometimes, ignorance really is bliss.
Do not ever use The Pod disc clamp. It requires you to put downward pressure onto the spindle and can damage the main bearing. The three feet can also cause a degree of deformation of the vinyl, but this is less severe than the former problem. Modern clamps such as the SOTA, Michell, etc. avoid both of these problems in various ways. Don't cheap out when your precious vinyl and turntable are at stake! The real theoretical advantage of using the Ringmat is that bearing noise and platter/plinth borne vibrations are not easily transferred to the disc itself. The drawbacks have already been mentioned.
Mr. cheapskate;
If the difference is a 16th of an inch or more, I would tend to think that you would hear a difference because of vta. I haven't heard the arum beta, I'm also not sure of its stylas shape, but if you are critically listening to the differences in these mats, and are hearing the differences, I don't see why you wouldn't hear a difference in vta.
One thing that leads me to believe this is that I have generally found that aq mat to sound more on the dark side. although if it's taller, that would tend to make the bass less defined,sometimes I find the bass to get more defined when I get into the best spot, as opposed to vta to high in the back. Also, the lower ringmat and the sound you describe would support this.
But, the differences you describe also support what I hear are the differences in these mats.
So the only way you can find out, is to find out. to keep track of vta, I take a business card, set the stylas down on the inner groove of a record, and mark on the business card the top of the tonearm at the farthest point forward and at the farthest point back at the lead-in groove. Genarally, most cartridges will be about 1-2 millameters down at the back, which will translate to about 1/8th of an inch at the base of the arm.
You could also try different combos of mats to try to keep all the heights the same, if for nothing else an experiment in finding the ideal vta.
Finally, anther point is that your average repair shop will not make concessions for vta if your turntable/arm doesn't support it. So evan if he did a respectable job, your vta could be way off. If you find that so, you could find where you want it and take steps to put it there.
And finally again, while I agree with you sean, I disagree. Your theories are sound, and they are true, and your knowledge is high, so is the quality of your analog replay system. This is a thoerens. While it is better to have a disk solidly anchored to avoid resonences, you have to consider what you are anchoring it to. If resonences reflect, that can be worse, and what will be more effective in controlling them will have as much to do with the nature of the resonance as much as the attenuation of such, nature being the particular frequencies and the reaction of how they are coming about. The fingmat, for instance, is not really meant to be a flimsy way to float the record above the platter, but rather is desighned to solidly anchor the disk while isolating it from the platter, (cork is stiffer than rubber), while at the same time, supplying resonence control by virtue of the distance of the rings. If you had a linn, or a theorens, how would you couple the record to the steel?
And finally once again finally, there is nothing wrong with tweeking around with that thereons. Its just as fun in my book to tweek out a less expensive turntable as it is any. And the results could be more impressive.
Thank you all for your comments. It's so nice to find like minded individuals that write extremely graphically explicit technically confusing sentences that need to be read a half dozen times!

An interesting side note: I had been using a tweaked out Fisher 800C receiver (1960's top of the line, best all tube receiver ever made) until two days ago, when I subbed a CJ PV-5 tube Preamp into the system (still using the Fishers 32 RMS per amp section.)

The most profound differences were in gain and bass response, which in turn wrecked havoc with my turntable. I had had 2 five-pound lead weights on two corners of the chassis. They were a desirable tweak, until the newfound gain and bass response caused impending subwoofer meltdown. I’m sure most of you can imagine the cycle: a little rumble causes unwanted bass response, which causes vibrations, which in turn cause more rumble.

Removing the weights, I experimented with the three different mats and clamping and unclamping, adjusting to produce the loudest bass I could play without overload using B. B. King’s “You’re Mean” off the “Completely Well” album. The sorbothane mat with clamp won.

I experimented with cones up, down, rubber, and sorbothane hemispheres in various combinations on my Target turntable rack. The best combination occurred with a Vibrapod shaped piece of rubber (marketed to be used to mount machinery for vibration control) directly on the Target MDF, with a Black Diamond cone pointing upward on top of it, with the Thorens mounted on top of three of those rubber/cone doohickeys. I’m not done tweaking (could God build a system so good that even he couldn’t tweak it?), but at 106 dB I think the stabilization is mostly taken care of.

With regards to the writer that wrote that the Pod DisClamp should never be used, I’m a big guy—6-3—with big hands. The trick is to support the platter with the fingertips while using the thumbs to engage the clamp. A trip to the hardware store suggested by another writer produced an assortment of washers, including a very flat one just smaller than a record label that I glued some felt to that compensates very well for the otherwise relatively uneven downward force cause by the three prongs of the clamp.

The Cheapskate loved how the 69cent Vibrapod shaped piece of rubber outperformed the $60 Audioquest Sorbothane hemispheres, as well as the assortment of washers I got for 82 cents.

Keep those cards and letters coming,
The CheapSkate
I love your tweeky method of overcoming the shortcomings of the Pod. Great work. That's what the hobby is all about.
Basement, thanks for kicking me in the head and knocking some sense into me. Sometimes i tend to look at things as trying to set them up for optimum performance and forget that not all components / installations are up to the task. As such, i need to remember to take the specific components being used into account. This is not to say that the Thoren's is not capable of working quite reasonably, but to say that i might have been giving it a bit more credit than it deserved and taking things for granted.

I think that Brtritch found out the limitations of his installation the hard way i.e. running into problems with acoustic feedback, etc... When you start getting into high SPL's and have the capability of low bass with great authority, you really have to work on your TT installation. Luckily, it appears that Brtritch has found a suitable solution for not that much money. Too bad all of our problems aren't that easily solved : ) Sean