When I agreed to review the Carbide Base isolation devices, Jeffrey Jenkins asked me how many sets I needed for my system–a common question when it comes to reviewing these types of products. I said yes to three sets of four Carbide Bases (or four sets of three footers), for a total of twelve devices. When I headed to the local hardware store to pick up the box from Carbide Audio–I live in the middle of nowhere now, so that’s the new drill for FedEx and UPS–I was surprised that I could barely lift the box and drag it to my car. These things are big and heavy, so much so that I knew I needed to employ them in a different manner than most isolation devices.
Words and Photos by Marc Phillips
If you haven’t noticed, I’ve opened up the flood gates to isolation devices over the last year–mostly because I think they’re so important. I’ve tested products from Les Davis Audio (light), Fern & Roby (light) and Ansuz Darkz (more substantial and heavy but still small enough to hold in an enclosed fist). I can also mention the roller-ball bases from the Nola Champ S3 and Baby Reference Grand 3s, which are part of the speaker design. Plus, you only need one for each speaker, not three or four.
In fact, I’d have to go all the way back to the $4,000 Harmonic Resolution Systems isolation shelf I used with the Brinkmann Taurus turntable before we’d be discussing something bigger and heavier than the Carbide Base products. All of these isolation products provided a clear and consistent improvement to the overall sound of my system. But here’s the most surprising part about Carbide Base isolation devices–they’re pretty affordable despite their formidable appearance–just $299 each.
I should have known that these isolation bases were going to be big and massive when Jeffrey Jenkins told me to use them underneath my speakers. I usually try not to use any such devices under speakers and stands, other than a few wads of Blu-Tac, because in my experience they do two bad things–they raise the level of the tweeter which can compromise the intended design parameters, and they can make the whole loudspeaker/stand/floor interface just a bit more wobbly. But looking at these Carbide Base isolation devices, I merely thought, “Sure, these’ll work under any speaker or stand I can think of. They ain’t going anywhere.”
Inside the Carbide Base
The Carbide Base has a rather complex approach to isolating components from noise and vibration, based on the idea that the device addresses all “six degrees of freedom.”
“Separate upper and lower portions are designed to optimize vibration isolation and dissipation in vertical and horizontal directions. The upper portion utilizes an aluminum housing machined to accept a specially formulated viscoelastic member called ViscoRing™. The ViscoRing™ acts as a damped spring supporting the equipment while isolating it from vertically oriented vibrations. It is replaceable depending on the intended supporting weight range.
“The lower portion incorporates zirconia ball bearings and viscoelastic elements to enhance horizontal isolation and damping. The large bearings roll on raceways formed from polished hardened steel to minimize rolling resistance. The bottom can be unscrewed to facilitate nearly 3/4″ (20 mm) of height adjustment.”
Some more details on the unique design, again cribbed from the website:
“When it comes to viscoelastic materials providing isolation, more is not necessarily better. It is the low ratio of surface area supporting weight to the surface area free to bulge outward which is important for improving isolation performance. The term for this ratio is Shape Factor. The lower the Shape Factor, the greater the potential degree of isolation.
“Carbide Base audio isolation feet implement viscoelastic materials with Shape Factors far lower than previous designs. The large tubular shape of the ViscoRing™ maximizes the surface area that is free to bulge. This yields a Shape Factor around half of the lower limit traditionally used for elastomeric isolators. The low shape factor is made possible by the patent pending design of the Carbide Base footer. Ridges within the upper portion progressively brace the ViscoRing™ as it compresses to stabilize it while leaving a substantial surface area free to bulge.”
While the Carbide Base is designed for loudspeakers, especially those with heavy stands or existing footers, they can obviously be employed under just about any component with equal success. As I’ll mention in a bit, you may add several additional variables to maximize the effect of the bases–mostly when it comes to elevating your speaker. I know that for many loudspeaker designs, the height of the drivers in relationship to the listener’s ears is critical. (Many audiophiles, including me, instinctively raise their speakers so that the tweeters are at ear level, but this isn’t true for every single design.) What I’ve found, over the years, is that your room and your listening position are also vital factors. That’s one of the reasons I’ve maintained a “reviewer’s” listening room where there is plenty of space to work with, and that furniture can be moved around to accommodate an optimal set-up. So if I’m worried about the level of a tweeter in relation to my ear, I can usually ameliorate the problem by sliding my chair up and back.
That opens up the door to the Carbide Base. Since I’m already pushing sofas and loveseats and chairs around to come up with decent results for a loudspeaker, I had no issue with doing the same for isolation devices. Not once, while using the Carbide Bases, did I feel the addition height somehow compromised the sound quality.
When it comes to placing the Carbide Bases under components, it’s as easy and trouble-free as it gets–with the minor caveat that it can be a bear to lift up a heavy amp and carefully place it on the bases without things sliding around capriciously. I was tempted to use a few balls of Blu-Tac to keep it all steady, but I didn’t want to compromise the design of the Carbide Bases. But if I bought a set for my own personal use, I’d give it a try.
This section differs from most reviews in that I tried the Carbide Bases in a number of system configurations. Every time a new system was built when new gear arrived, I immediately thought of how the bases could be used.
So I’ve detailed the results in a number of configurations, described in detail below. One thing I wanted to discuss, however, was how to adjust each Carbide Base to maximize the results. First of all, you can choose between five different ViscoRings to be installed inside the base according to the amount of weight of the component. Each of the five ViscoRings come in different colors so you won’t get them mixed up–the green ones are designed for up to 35 pounds, the silver-gray ones handle up to 70 pounds, the blue ones handle from 40 to 140 pounds, the black ones handle from around 100 to 280 pounds, and the red ones handle up to 800 pounds. (These weights are based on a set of four, not for each base.) You can buy additional ViscoRings so that you can adapt them to anything in your system. Since I didn’t have a D’Agostino Relentless monoblock sitting around, waiting to be used, I was perfectly fine with the blue and the gray ones. The heaviest I tried was the Gershman Studio XdB speakers, which still weigh a reasonable 67 pounds per side, with stands.
Second, you can adjust the height and the tension of the Carbide Base by simply spinning the top plate, which moves as freely and efficiently as that VTA wheel on a Technics SL-1200G. A simple tool is provided to help tighten the top plate so it won’t be slowly moving in one way or another over a long period of time. It’s almost like having an old Linn LP-12 turntable–it sounds great, but it needs re-adjusting every so often.
Impact on Sound
Notice how I didn’t say, “Carbide Base Sound” in this header? Because some of you will say that isolation bases shouldn’t have a sound. And yes, that’s probably true in a hinky, skeptical kind of way. But an isolation device should reduce vibrations and provide suitable damping for whatever is placed upon them, and that results in less noise, and that allows more of the music to come through, which is the main purpose of using isolation devices and proper grounding and chassis materials that don’t stir up inductance and eddy currents and whatnot. In other words, the Carbide Bases will be judged on their ability to impact the sound.
I’ll admit that the results varied. On a component that is already built like a tank, such as the Antipodes Oladra music server and the Innuos Pulsar network streamer, the Carbide Base made little to no difference. (In both cases, the stock feet are quite impressive already.) But take a component such as a CD player or even a DAC, which has a lot of internal parts that make their own vibrations and noise, the Carbide Bases provided clear improvements to the sound.
Yes, the improvement in sound usually followed the predictable and somewhat linear impact that most noise suppression products–everything from grounding devices to ethernet switches–in that the Carbide Bases helped to lower the noise floor of the system. Excess noise in your system can sound like several different things–a blurring of the sound, a dulling of transients, and a loss of detail. When you install a device like the Carbide Base, the sound comes into focus. You hear it and your brain seems to need less effort to make sense of the musical presentation, especially with complex musical passages. The Carbide Bases definitely passed that test.
On loudspeakers, however, I had different results. I did hear all of those things I heard when the bases were placed under components, an overall clearer and more transparent sound, but I started to notice an immediate improvement in the deepest bass. Sure, lowering the noise floor makes it easier to detect more details and textures in the lowest frequencies, but I suspect the Carbide Bases are so remarkable in this application because they also couple the speaker to the floor in a more secure and precise way.
Carbide Base Listening Sessions #1–Gershman
When I first read that the Carbide Base isolation devices could be used under speakers and stands, I hesitated to try them out. First of all, I normally use the Acora Acoustics SRS-G granite speaker stands, which weigh about 100 pounds each. Combined with a heavy monitor such as the Piega Coax 411s or the Gershman Acoustics Studio Xdbs, which both weigh more than 60 pounds each, I worried that I’d be returning a bag full of carbide dust instead of the footers, even though the weight ratings for each ViscoRing was supposed to assure me that it would work. Mostly I didn’t want to return the Carbide Bases all scratched up and dented.
Turns out, I really needed the Carbide Base footers under the Gershmans since the carpet in my new listening room has a lot of padding. The SRS-Gs usually circumvent that issue due to their mass, but the Studio XdB, with its integrated stand, is already quite top heavy. With the IsoAcoustics Gaia footers that came with the Gershmans, the entire speaker was quite wobbly and prone to fall over like a Jeep Wrangler with a leaf-spring suspension. (Gershman Acoustics does offer spikes for the Studio XdB if needed.)
I first wound up using a combination of the IsoAcoustics Gaias and the Carbide Base footers for a couple of reasons. First, when I used the Carbide Bases alone, there was still an issue with the top-heavy speakers falling over at the slightest bump. Although the combination looked a bit more precarious, it was far more stable. Second, the interface between the two footers was flatter and far more secure.
Listening sessions revealed plenty of sonic differences, but I have to be careful to consider the raised height of the Gershmans and whether or not that was the main contributing factor. But I also found that the Carbide Base footers and the Gaia footers raised the tweeter almost to my ear level. While this temporary solution may draw the ire of Eli and Ofra Gershman for one reason or another, I felt that the combo tightened the focus within the soundstage without affecting the ample bass output (the Studio XdBs can reach down to 23 Hz!). The wobbling wasn’t completely addressed–these speakers need spikes or bare floors in stock form–but I felt more confident that I could leave them under the XdBs.
If you’ve read my review on the Gershmans you’ll notice that I found the Carbide Base footers effective, but not 100% ideal for the job. Over time, the Carbide Base footers settled into the thick carpet, but due to the top-heavy nature of the Studio XdBs I still felt that I could knock them over with one good butt-bump. After that review appeared, Carbide Audio noticed and said, “Let me send you some spikes!” I’d noticed the three threaded holes in the Carbide Base and wondered about them, but it all made perfect sense. I received plenty of spikes, installed them, and it was a whole new ball game. The Studio XdBs were tremendously stable on just the Carbide Bases, and they proceeded to show off even more potential by throwing a more stable image and even deeper bass–which the Gershmans already did very, very well.
I found another effective use for the Carbide Bases shortly afterward. There are times, of course, when my equipment rack gets full of gear and I have to place an extra box or two on either an old Target amp stand that I normally use for my AudioQuest Niagara 3000 power conditioner. Since there is no “bottom shelf” on my Fern and Roby equipment rack, I sometimes place components directly on the floor underneath the lowest shelf–there’s plenty of room. That didn’t present a huge problem in my last couple of homes–hardwood floors. That’s where the thick carpeting in my new listening room once again reminded me of its stubborn resistance to all things audiophile.
Most electronics, especially power amplifiers, need ventilation underneath. Too much heat, of course, can shorten the life expectancy of your component and perhaps even start a fire. (I made this mistake many years ago and yes, the carpet was charred and I didn’t get my security deposit back from the landlord.) But the Carbide Base was ideal for keeping the Ayre V-3 power amplifier and my Pureaudio Control preamplifier off the carpet, and they looked damned good doing it.
I used the Carbide Base extensively in my headphone rig, which sits on top of a beefy oak coffee table in my living room. I constantly use all sorts of isolation devices on the coffee table because it’s not quite audiophile-approved, and these devices always yield big improvements in noise reduction. When it came to larger, heavier components–my Unison Research CDE CD player and the Audion Silver Night 300B headphone amplifier, for example–the Carbide Base was unusually effective at reducing all kinds of noise from the system. With the Audion, for instance, I heard some tube rush from the 300Bs–not a big issue, but having effective grounding in my main system highlighted what they could do in my headphone rig.
Once the components became smaller and lighter, the Carbide Bases became slightly less optimal. For example, I thought the Carbide Base would be perfect for elevating the tiny MonAcoustic SuperMon Minis off the coffee table to emulate a classic desktop system. But the bases aren’t perfectly flat on top. They’re gentle raised in the middle to create a very shallow cone, with one point of contact between the base and the component. (Refer back to the Shape Factor, discussed above.) So one Carbide Base, which seemed right at first, made the Minis wobble constantly. And three Carbide Bases were simply way too big to fit underneath the Minis without taking up too much space on the table.
That’s more of an issue with the size of the Minis, of course, and I think the Carbide Base would be more ideal if you were using something larger–like an LS3/5a–for your desktop system.
Carbide Base Conclusions
Yes, the Carbide Bases from Carbide Audio are big, which may prevent them from being a panacea to all of your noise suppression needs. Where they fit, they worked splendidly. But as their primary use as a replacement footer for your loudspeakers, they are superb. In the past I’ve had issues with loudspeakers, especially stand-mounted ones, that just won’t couple to the floor in an optimal manner. In retrospect, the Carbide Base would have been the proper solution.’
While a couple of sets of Carbide Bases will easily increase your loudspeaker expenditure by a couple of grand, I think they’re a bargain when you look at how they’re built, what’s inside, and how gorgeous they are. You can also spend some extra dough to get the Diamond insert version of the Carbide Base, which replaces the stainless steel bearings with ceramic ones, and adds a Diamond PVD coating to the ball bearing raceways.
“Concerning the Diamond version of the footer, it actually adds a completely separate additional isolator into the top of the footer rather than replace any of the bearings on the standard footer. To upgrade to the Diamond version, the stainless steel section you see in the top center is pulled out and the Diamond Insert is dropped in its place. This optional upgrade can be performed at home.”
As Carbide Audio also explains, “the extreme hardness of the raceways allow for additional filtering of low-level noise via the concept of vibration Transmission Path Evasion.” The Diamond insert knocks the price up to $599 each. For audiophiles who balked at the $299 figure, this won’t change their opinion, but I do suspect that people with very expensive loudspeakers would want nothing but the best.
All that aside, I really enjoyed playing with the Carbide Bases and seeing how they could improve–without question–the clarity, transparency and overall performance of my audio system. Highly recommended.