Mi Rollers
A Brief Review Of Vibration Control

Review By Rick Becker
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  It should be no surprise to regular readers that I've reviewed more than my share of vibration control devices. I'm very big on them.  And this fact did not escape reader Richard Patrick of Lake Butler, Florida.   Richard bombarded me with exuberant email proclaiming the miraculous virtues of Mi Rollers until before I knew it, I had two sets in house for review.

As you can see in the photos, they are quite curious looking, reminding me of walnuts machined from either brass or aluminum.  I was sent a tall set in aluminum and a short set in brass. The machined waistline raised my curiosity, suggesting that they were made of two halves and perhaps filled with oil. I put that inquiry aside, along with the rollers, not wanting my perceptions influenced by construction details or theory.

The next round of incoming product for review happened to be the new Von Schweikert VR-4 Jr. loudspeakers ?a brand new pair with 400 hours of loud break-in requested before critical listening.  I set them up in my stereo video rig.  The music was pretty difficult to ignore as I went about my life, so I slipped the Mi rollers and a Symposium Isis shelf under the inexpensive DVD player and the vintage Tandberg 3012A integrated amplifier.  As impressive as the VR-4 Jr.s were right out of the box, the music improved quite noticeably with the addition of the Isis selves and Mi Rollers. The two worked well together because the large rounded surface of the rollers was not sharp enough to dig into or puncture the surface of the moderately priced Isis shelves.

The lightweight DVD player jiggled easily on the Mi Rollers when touched, and the much heavier Tandberg presented more resistance and came to a halt more quickly when pushed in the horizontal plane.  These results were a good sign, as that is basically what happens with the Symposium Rollerblocks I use in my reference system. The manufacturer recommends putting additional weight on top of very light components, but I didn't do this during this casual listening stage of the review. In watching the components dance, it occurred to me that the  Mi Rollers incorporated both the concave surface of the Rollerblocks with the concept of the ball bearing뾞ll in one machined part!  Very clever, indeed!

 

Three Major Ergonomic Benefits

Three major benefits of this design came to light in the early stages of my playing with the Mi Rollers.  First, I slipped the shorter (19mm) brass set under my tuner to listen to Hearts of Space on Sunday night.  They lifted the feet of the tuner a mere 1mm above the shelf, which is excellent, because there is very little headroom above the tuner in my rig.  Had I needed an extra millimeter of clearance to lift the feet off the shelf, little squares of plastic laminate samples from Home Depot were close at hand.  Even the tall (25mm) Mi Rollers are not as tall as the Symposium Rollerblock 2+ (30 mm), Rollerblock Jr. (32 mm), or Stillpoints with risers (36 mm). Only the Stillpoints without risers (25 mm) compare with the taller Mi Rollers.  While these distances are not huge, when combined with the ergonomics of installation of the various devices, they become more significant.

The second ergonomic benefit was the ease of placing the Mi Rollers under components.  There is no tricky balancing involved here. Just lay the Mi Rollers on the shelf, preferably not in a straight line, and set the component on top of them.  Alternatively, if the component is already on the shelf, just lift an edge and slide them under, one at a time.  I usually placed them in a large equilateral triangle. When set down, they take a few seconds to stop their rocking motion. A push with a finger from the front of the component and again from the side of the component will tell you if it is properly placed.  It should jiggle readily in both directions.  This is so easy to do that I took them to a 150 year birthday party (Ralph and Janet, age 80 and 70) and slid them under the audio rig I had set up for them.  Only the stamped metal bottoms of inexpensive components which tend to contain a variety of indentations pose any real challenge to placement of the Mi Rollers. Using shims under one or two rollers would allow for some degree of leveling a component.

The third ergonomic benefit is their stability.  The component will not roll away on you, although the Rollerblock Jr. and Stillpoints are also very good in this regard.

Only with a lightweight carousel multi-format player with its heavily indented bottom and large tray did I have any fear.  When the drawer closed it sent the entire unit into a rocking motion that might have caused a roller to slide into one of the valleys in the floorpan. With more typical High End gear I had no problems.

 

Do They Work?

In my earlier reviews of Symposium Acoustics Rollerblocks and shelves, and Stillpoints, I have already established the importance of having some kind of dampening device in use with each component.  The synergy builds as each successive component is dampened, and the weakest link is strengthened.  On many of my components I combine more than one device for even greater improvement.  (See my detailed description of the rig far below).  Since I don't feel the need to prove this synergistic effect again here, I decided to test the Mi Rollers under the CAT preamplifier and compare the results with the Symposium Rollerblock 2+ and Stillpoints with risers.

Listening to an old favorite, Buddy Guy's Damn Right I've Got the Blues, I replaced the Symposium Rollerblock 2+ with the low brass Mi Rollers placed directly on the solid maple shelf.  The music was just as transparent, but the decay of notes was longer and the attack not quite as sharp. I noted the CAT did not sway easily when I pushed it.

Next, I placed the Mi Rollers on top of the stainless steel plates that come with the Symposium Rollerblock 2.  Focus increased, not quite to the level of the Rollerblock 2+, but close.  The CAT swayed a good bit more freely than before, but not as freely as with the Rollerblocks.  A little bit of over-ringing was noted on high piano notes, in particular, indicating the decay was still a little long.

At the suggestion of Richard Patrick, again, I substituted ceramic tiles (7.75" square by 5/16" thick) for the stainless steel plates under the Mi Rollers.  Focus improved even more, to almost the level of the Rollerblock 2+, but again, without the edge or bite exhibited by my Kharma loudspeakers when the Rollerblock 2+ were under the CAT preamplifier.  We are really high on the High-End Mountain, here, and dealing with very subtle differences.  Personally, I appreciate the musical edge that the Kharmas give me without crossing over into irritation.  It contributes to the "you are there" experience. Others, who prefer their music to be more relaxing, might appreciate the slightly backed-off results achieved with the Mi Rollers.  With both devices, however, the pace, rhythm and timing were all improved by the increase in focus they imparted on the system.

Next I swapped the taller aluminum Mi Rollers for the lower brass version, keeping the ceramic tiles in place.  The larger rollers seemed to have slightly better focus, but it lost some of the mellowness or body of the music with the brass version.  On a particularly bass-heavy cut, there seemed to be more bass energy with the larger Mi Rollers, but the bass was fuzzier.  I'm sure I was stretching the limits of my Manley Mahi monoblocks here, which I run in triode mode with minimum feedback, yielding only 20 lovely watts per channel. On everything else I listened to on this CD the bass sounded very good.

Of course, I'm not really comparing apples to apples here.  The acoustic benefits of brass are widely known.  Like꿾hen was the last time you heard an aluminum trumpet? And there seemed to be clear improvement in focus when going from the shorter to the taller Mi Rollers. Ideally, I would have had both brass and aluminum rollers in each size, but think I've picked up on the critical differences, nonetheless. Interestingly, the aluminum rollers seem to be a lot lighter than the brass, suggesting that the rollers are indeed hollow, or filled with liquid.  They both seem to be a lot warmer after use than mere conduction would account for again, suggesting that some motion was converting mechanical energy to heat in the process of dampening vibrations.

Continuing on, since I had no spare set of Stillpoints, I put the CAT power supply on the larger aluminum Mi Rollers and put the Stillpoints under the CAT, ceramic ball down on the ceramic tiles. This combination proved superior, even to the Rollerblock 2+.  But in all fairness, I then had to try the Rollerblock 2+ with the ceramic tiles. This required using the Rollerblock 2+ in the "ball-up" position with the stainless steel plate on the bottom of the CAT and the ceramic tile beneath the Rollerblock. This brought the performance of the system very close to results achieved with the Stillpoints.  With the Rollerblock 2+ on ceramic tiles, the music was a little more liquid sounding. It was slightly drier with the Stillpoints nose down on the ceramic tiles. In all other parameters, with the limited music material I had time to investigate, there was little or no difference.

To satisfy my curiosity, I went a step further and inverted the Rollerblock 2+, placing the upgrade tungsten carbide ball directly on the ceramic tile with the Rollerblock in contact with the bottom of the CAT.  This gave me more liquidity, more involvement with the music, and more of why I prefer the Mahis in the 20 watt triode mode rather than 40 watt ultra linear.  Clearly, the ceramic tile is making a significant contribution. With generic tiles of this size costing about a buck, this is something to investigate in your own system if you have the slightest inclination.  Richard reported to me that he had improved results by stacking multiple tiles beneath the Mi Rollers, although I haven't felt inclined to follow that direction.

Getting back to the Mi Rollers, I placed the smaller brass model on the ceramic tiles once again. Damn!  This sounds really good, too!  It lacks a bit of dynamics compared to the Rollerblock 2+ and the Stillpoints, but it gives a tighter bass and most of the focus you get with the higher priced models.  Double checking the larger aluminum model, I was convinced that larger is indeed better than small, as the dynamics definitely improved ?not quite to the level of the Rollerblock 2+ or Stillpoints, but close.

I then removed the larger aluminum MI Rollers and let the CAT rest directly on the ceramic tiles.  This resulted in a very significant degradation in sound quality. Bass, especially, became muddy, but the loss of resolution was across the frequency spectrum. Next I removed the ceramic tiles and once again let the CAT sit directly on the solid maple shelf.  Predictably, the resolution dropped again.

 

Summary

If you haven't already tried some sort of vibration dampening device under your components, surf the web for reviews, check the back issues of your print journals, bite the bullet and buy something!  Then try it under a variety of your components and see if you don't think you could benefit from more of the same, or more of another variety. Each design has its own ergonomic plusses, and each design has its own level of resolution enhancement. From the two shelves and five devices I've now reviewed and use in my reference system, I can tell you that you pretty much get what you pay for. The cost of the last few degrees of improvement rises exponentially in high end audio, as we all know.  And the various manufacturers seem to have figured out the formula, by and large.  Once in a while you will find a wild card, such as the ceramic tiles, where the manufacturer doesn't even know they are in the game.  But as a class, while these devices may cost hundreds of dollars per set, they offer an improvement equivalent to thousands in component upgrades.

The Mi Rollers proved to be a very competent resonance dampening device with user friendly ergonomics.  While costing roughly half as much, they came very close to the performance of my best resonance control devices, especially when a ceramic tile was placed beneath them.  The improvement in focus, with the accompanying improvement in pace, rhythm and timing is readily apparent. I definitely recommend them to everyone from entry level to serious enthusiasts, whereupon your wallet will determine if you need to go any higher.  If listening to tonight's broadcast of Hearts of Space is any indication, the Mi Rollers will have a permanent home beneath my tuner, and possibly elsewhere in my reference system.  I certainly enjoyed the music.  The manufacturer suggests that they are also very beneficial to video images when used under DVD players, but I did not proceed in this direction.  Perhaps you might like to.

And once again, I give a tip of the hat to Richard Patrick for tuning me in to these little gems, and the benefit of the ceramic tiles.  Much more fun with these lies ahead.