Evil Vibrations

I think there was a time, long ago and far away, when audiophiles didn’t obsess about things like equipment isolation. I don’t really know. It’s hard to focus past my own OCD.

The bogeyman here is vibration. It comes from everywhere. From the air. From the ground. From the system itself. Unfortunately, a lot of those vibrations are tough to find or notice, much less eliminate. The problem that these vibrations pose is that its possible that they affect the performance of the gear they intrude upon. Speakers can sound congested. Gear can sound brighter or darker. It’s possible that simply addressing vibration can do quite a bit to the performance of the system as a whole. Heck, it’s a theory, right? Onward!

I have a Samson Rack from Mapleshade. The rack is comprised of blocks of air-dryed maple sandwiched between brass nuts that spin around threaded posts.

Isolation, with Samson, is a function of “a massively solid, really rigid rack designed from the ground up for resonance-free, maple-based vibration control”. I think the idea is that the maple shelves themselves somehow absorb both environmental and system vibrations. Mapleshade’s Pierre recommends that we use brass footers to couple the gear to the maple platforms, which then drains the vibrations from the gear into the wood, dissipating them.

I have my doubts as to the efficacy of “draining” vibrations. Vibrations are local and gear — whether speakers or amplifiers — are made of non-rigid materials. Which means that those materials themselves attenuate vibrations. Two questions: one, will any “draining” occur before or after detrimentally affecting the performance of the unit? Two, how much “draining” will any component really need and where would it need it? To truly address component vibration comprehensively, you’d need to damp/drain every inch of the unit’s surface, which is, ah, impractical. Especially when you’re talking about speakers. For me, I choose to trust that the designers knew what they were doing, so I think it’s more important to eliminate the effects of environmental vibration on the gear, that is, external vibration, not internal.

Getting back to Samson. I think it’s possible that the thick Maple shelves provide some degree of isolation. Also, I think that the brass is probably not as effective as I’d like. They look nice, sure. And honestly, I worry that the direct coupling might simply provide a path from the big brass footers, up the poles and across the brass nuts to every single platform. Said another way, my concern is that everything affects everything else on a rack like this. Everything depends on how effective the maple shelving is at swallowing the bad stuff.

Addressing Seismic (Vertical) Vibration

Barry Diament, a recording engineer, has a great article on vibration. He recommends “floating” gear in order to address what he refers to as “seismic” vibrations.

I’m still having a bit of trouble accepting that the ocean tide or the wind or a truck changing gears 1/4 mile away has such a profound effect on the performance of my audio and video gear. What I have no trouble with is the results of isolating my gear from these effects….

Seismic isolation. Those two words are the key to knowing what your components can and cannot do. The benefits extend to loudspeakers as well. In fact I have yet to find a component that doesn’t significantly benefit from seismic isolation. Some, like source components (for example CD and DVD players) and loudspeakers show the largest improvements but even power strips benefit from seismic isolation. After all, they too contain electrical signals which are subject to degradation by seismic interference.

How do you achieve seismic isolation? You have to “float” your components. Floating is accomplished with the use of simple mechanical low-pass filters. Mechanical low-pass filter is a fancy way of saying a spring with a resonance frequency in the seismic range. Every spring has a resonance frequency, which is the number of times it bounces when compressed and released. If we could float our components and speakers on some type of springs with a resonance frequency of only a few cycles per second or less, we’d be able to prevent the damaging vibrations from entering those components and the gear would be free to perform its best.

Vertical springs aren’t enough though. Vibrations can exist in the horizontal and rotational planes as well. We need to float the gear both vertically and horizontally. This is not at all a difficult thing to do and the performance benefits will make you wonder why this isn’t much more widely discussed. More importantly, the benefits will allow you to know the capabilities of your present components. I guarantee you will be very pleasantly surprised.

Barry’s article has a great description of how to “roll your own” using a partially inflated bicycle innertube, a plinth, and some ball-bearings sitting in egg-cups. I haven’t actually tried it, but he’s quite adamant about the effectiveness and I see no reason to doubt him. In some of the various forums that Barry visits, he’s discussed how he floats his Magnepan speakers, and how big the performance gains have been. Everyone who’s taken him up on it have been enthusiastic. Which makes me wonder. Is there a better solution? And if not, how would I do this with commercially available products?

So, let’s take a look at some commercial solutions. First up is Solid-Tech.

The Solid-Tech has several isolation products. At the high end, they offer their Feet of Silence ($600/set of 4). They scare me a little bit, but Solid-Tech assures that they provide the highest degree of performance for a component footer.

Coming down the line, Solid-Tech’s Discs of Silence look like little trampolines. They have a resonance of about 5Hz (excellent) and so provide isolation starting around 8Hz, which is about where you want it. They’re $295 for a set of four, which can support a load of up to 200lbs. They are also available as a $100 optional upgrade on their top-of-the-line Racks of Silence.

A cheaper option is also on offer from Solid-Tech, their IsoClear footers.

Interestingly, the isolation performance of the two low-end solutions from Solid-Tech are very similar and both are excellent. Their test results can be downloaded from here. Pricing for the IsoClear footers is $120 for a set of 4. Given their performance, I think this is probably the best deal going for “floating” gear. Of course, it is just a set of springs ….

Solid-Tech’s numbers indicate that their footers provide significant rotational and horizontal vibrational absorption as well as vertical. That’s 3-D attenuation! You can use whatever rack you want with these footers, or even no rack at all, just set the footers down on the carpet and slap a plinth on top. Bam!

Addressing Lateral/Rotational Vibration

Barry believes that an additional step is required here, something I’m not sure that Solid-Tech would agree with, but in the spirit of total overkill, let’s explore.

Barry’s comments, cited above, indicate that the Solid-Tech spring solution is a great fit, but only for vertical isolation. He still prefers a second solution for horizontal/rotational isolation. The approach? Ball-in-a-cup. More specifically, a metal bearing sitting in a metal “bowl” that would allow the bearing to move as necessary to accommodate and alleviate the other seismic interactions. The bearing and its cup must be very hard and very smooth so as to allow free movement. Of course, using them will create a firm vertical coupling with the component that sits on them, but if you float the platform they rest on, you’ll have a perfect two-stage solution.

Commercially, there aren’t a lot of options here, but the one that comes to mind is from Symposium. Their Rollerblocks are precision machined and come in a variety of options to extract that tiny extra bit of performance.

The “basic” set of Rollerblocks will set you back $400 for a set of three, which isolates a single component. Now at Version 2+, the Rollerblocks include (as standard) bearings that are made from Tungsten Carbide. This is crazy-hard stuff. For comparison, $500+ custom-made kitchen knives forged using state-of-the-art processes typically have a Rockwell hardness rating in the 60-65 range. This is a significant improvement over your typical Wusthof, whose Rockwell rating is in the mid 50s. (See here for a fuller discussion). The Tungsten Carbide bearing has a Rockwell rating of about 90. Why should you care? Well, it ain’t gonna dent. Ever.

Not enough? Want more? Well, for those wanting the highest performance bearings made with the tightest tolerances, there is the “Superball“, for an additional $115/ball. Superballs. I love that. From Symposium:

As lateral vibration occurs, the bearing isolation device’s body slips and its ball (or balls) rotates. How well the system can isolate and dissipate lateral vibration is directly related to how fast its balls can rotate and respond to tiny amounts of lateral displacement. In this function, the quality of the ball is akin to the diaphragm speed of a very fast tweeter in its ability to correctly reproduce high frequency waves, although the ultimate function is opposite: in the tweeter’s case, it is making waves, and in the Rollerblock’s case, it is absorbing them. Any departure from perfection in roundness will cause the balls to “wobble,” and will also create disparity between the rotation rates of the different Rollerblocks. Each of these results of imperfection in roundness has its own damaging effect upon the job of the bearing isolation device. Wobble in the ball’s rotation causes additional vibration, which is in turn transmitted through the system, just like the vibration caused by a car tire that is out of balance. The Grade 3 ball’s nearly perfect roundness practically eliminates bearing “wobble” or non-linearity of motion. This reduces vibration further and makes for super-quiet and extremely linear behavior. Further, any ball-bearing isolation system with more than one ball (the Rollerblock system exploits the minimum number possible – one per device, for a minimum of three in establishing a plane) is affected if each ball is not absolutely identical in size. Imagine a system with three different diameter balls: each, for an equal amount of lateral displacement, rotates at a different speed. These different rotation rates induce directional “prejudices” and skew lateral motion. Thus, it is important that all the bearings be as identical in diameter (size) as possible. Diameter precision is another vital aspect of the Grade 3 Superball: if the diameters of different balls in the same system are different, the rotation rates will be different. If the rotation rates are different, the different balls will, in effect, “fight” each other and constrain each other’s ability to move freely and quickly. The super-uniformity of each of the Grade 3s minimizes problems in this area, and contributes to how the Grade 3 and the Rollerblock achieve their unparalleled levels of performance.

And there you have it. SOTA isolation for $740/component. Well, $740 plus whatever you’re using for a shelf and whether or not you’re floating that shelf on some springs.

Symposium has a less expensive solution, their Rollerblocks Jr.

The biggest difference between the Rollerblocks and the Junior is the that the latter are dual interface, with top-and-bottom cups, where the former is just a single-cup. Symposium suggests that the Junior is not quite as effective as the full Rollerblock, but with prices starting at $170 for a set of 3, the Junior solution is certainly more affordable. Options include a set with Tungsten Carbide balls (Grade 10, or, non-Superball) instead of the standard Chromium (called the Jr+), for $220. You can also get a higher-quality version of the Junior, originally designed for heavier loads, called the HDSE (Heavy Duty Special Edition), for $300, which also includes the Tungsten Carbide balls. Symposium suggests that the Superball upgrade ($115/ball) be limited to the HDSE as it uses a higher level of finish and harder aluminum, both required to get the most out of the Superballs. Note also that the Junior has a threaded hole on one cup so that they can be directly mounted onto components or speakers in place of the manufacturer supplied footers/spikes. Nifty.

What sits between

I think the only thing remaining is to talk about shelving and/or plinths that you can float on your Solid-Tech IsoClear footers and rest your Rollerblocks on.

Shelving and plinths are usually made of something like glass, acrylic, stone, metal or wood. I’m not sure what I’d recommend, really. Many audiophiles report that the sound of wood is the most natural and/or the most “warm” tonally. Not having had a variety of shelves to compare directly, I’m simply going to defer preference here. But in talking with my local dealers and reading copiously from the Internets, I think it’s fair to say that what you want is something that isn’t going to color your component’s inherent sound (unless you don’t like it). I suspect that wood is “warm” because it’s a bad isolator and that what’s warming the sound may well be the vibrational energy we’ve just gone to rather great lengths to attenuate. Therefore, if you have a component or system that you suspect is contributing to the brightness of your system, and for some reason you don’t want to replace that problematic component with something more neutral, you could try a wooden platform for it. Personally, I’m more in favor of letting the component do what it’s designed to do, so I think I’m going to lean more toward a composite of some kind that perhaps will add that last bit of isolation to the component in question and do it without coloring it.

Which brings me to Audiav. These folks make racks and shelves of rather extremely high quality. Everything they do is custom configured. They’ll want to know what gear you have before they’ll quote you on the solution they think is best for you. Apparently, they’re a bunch of know-it-alls. LOL.

While they sell a variety of different racks, what I’m most interested in is their platforms. Audiav is the only company I know of that takes serious pains to talk about EMI/RFI and heat dissipation in addition to things like vibrational isolation. Obviously, this could be important. I have a big Plinius amplifier that begs to be run in Class A — which means it gets quite hot. No, nothing like what a pair of Joule-Electra OTL monoblocks do, but still, it’s significant. With an Audiav shelf above it, I can be reasonably comfortable that I’m not cooking the component sitting directly above that amp. Also, Audiav platforms are available with options to support up to 1000lb loads. I have no idea why you’d need that kind of capacity, but what the hell. You can have it!

Unsurprisingly, there are some options when it comes to the Audiav shelves. Their top-of-the-line is the Master Signature series, which is a three-layer design; the Signature series is two-layer. That top layer can be granite, carbon-fiber, maple or composite, and in-between gets sandwiched interesting things like constrained-layer dampening or even an optional EMF shield ($200 for the Signature, $400 for the Master, which is actually two layers of the EMF shield).

Interesting side note about the optional shield. I asked a dealer “if I should bother” and he said, no, not at all. Unless you’re sitting something noisy right underneath a turntable or a phono preamp, it’s probably not worth it. He continued, “I mean, as long as you don’t have a Berkeley DAC in there, you’re gonna be fine.”

WTF? Um, well, now that you mention it, I do have a Berkeley DAC. He laughed. The transformers selected for that DAC are noisy — both audibly and EMF-wise — and were specifically chosen due to their performance relative to their cost. The dealer suggested an “EMF sandwich” for that DAC. Word to the wise ….

There isn’t really a price by the size, for everything but the granite, the size is up to 21″ square; granite is a 28″ square. Anything less is the same price, but they’ll cut to fit at no charge.

• Audiav Composite Signature shelf: $560
• Audiav Composite Master Signature: $870
• Audiav Carbon Fiber Signature: $1130
• Audiav Carbon Fiber Master Signature: $1440
• Audiav Granite Signature: $1800
• Audiav Granite Master Signature: $2260

The ultimate rack?

Which brings up another point. If you’re worried about dissipating vibrational energy, as well as limiting the impact of radiation and heat on your system’s components, then a single vertical rack is the way to go. The sandwiched components are unable to directly radiate into each other since they’re all shielded top and bottom. In this configuration, all radiation sprays leaks sideways.

Of course, this makes the above conversation a bit problematic. The bulk of the price in any given rack is the framework, and quite frankly, it may well be pretty much irrelevant if you float the individual shelves and their respective components. Well, then — I say go with aesthetics, and with something that gives you enough head room to stuff your gear (and shelf and both sets of footers) into, but either has no shelves or shelves that are completely removable. The Solid-Tech Rack of Silence might be a good fit here, or maybe SolidSteel for something a bit more affordable.

I think we could put together a Solid-Tech+Audiav+Symposium solution and stuff it into a SolidSteel rack. Perhaps if you used a SolidSteel 6-series rack and just dumped the shelves (can you order it without them?), with Solid-Tech IsoClear footers holding Audiav shelves? That’d be pretty spiffy, I think. And pretty pricey. But what price, perfection? LOL.

• SolidSteel 6.3 3-Shelf Rack: $1100.
• Solid-Tech IsoClear footers: $120/set of 4. 3 sets required. Total: $360.
• Symposium Rollerblocks Jr+: $220. 3 sets required. Total: $660.
• Audiav Composite Signature shelf: $560. 3 required. Total: $1680.

The ultimate in isolation? $3800 per 3 shelf rack. Bam!

Err. Ouch?

I think I need two ….