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Anti-vibration accessories
fo.Q - AB-4045R (audio board) ǀ G-53FS/G-51(High End Damping Spacers fo.Q) ǀ CS-01/CS-02 (carbon spacers +fo.Q)

Price (in Europe): AB-4045R – 570 euro ǀ G-53FS – 75 euro/4 szt. ǀ G-51 – 32 euro/4 szt. ǀ CS-01 – 160 euro ǀ CS-02 – 175 euro

Manufacture: KISO industry Co., Ltd.,

Contact: Toranomon 3-3-3 ǀ Minato-ku ǀ Tokyo ǀ Japan
tel.: +81 (0)3 3437 6133 ǀ fax: +81 (0)3 3437 6185

Manufacturer's website:

Country of origin: Japan

Products provided for testing by: MuSon Project, Inc.

Text: Wojciech Pacuła | Photographs: Wojciech Pacuła

Published on: June 1. 2012, No. 97

„‘fo.Q’ is a product applying materials developed with the support of JST (Japan Science and Technology Agency). Vibrational energy is converted to electric energy, and finally to heat energy, enabling efficient absorption.”
When it comes to companies like this one it’s a good idea to start with the information they provide for customers. Especially that – as usually when it comes to Japanese companies – we can find there a lot of technical information, measurements, and the idea behind this product. For it is not snake oil and some audio voodoo but an implementation of solid, hi-tech knowledge by smart, capable people – scientists and engineers, who happen to love music. Please, have a look at the measurements available on the fo.Q's website – then you will see what I mean.

fo.Q is both the brand that belongs to a large, Japanese company called KISO industry Co., Ltd, as well as the material they developed and which in fact lead to creating this brand. It is not the first such case when some industrial giant creates a small audio company to focus on some small area of the audio market – Acrolink is one good example (being a part of Mitsubishi Corp.). It usually happens when R&D department of that giant develops some new material, technology, etc., that one of the engineers or scientists working on the project successfully used in his own, private audio system. Let me repeat – these are hi-tech products/materials/technologies that would have never been developed strictly for audio due to immense R&D costs, but were actually created for other purposes and then used for audio. That's a great example of how we (audiophiles) can benefit from hard, costly labour of other industry branches. KISO industry Co., Ltd. also makes and sells this material (as OEM product) to other Japanese companies for their own use. Acoustic Revive would be the easiest and best known example – Mr. Ken Ishiguro, its owner, uses fo.Q in many of his products like, for example: CS-2Q and SIP-8.

As we read in the note provided by the manufacturer, fo.Q is a piezoelectric material that quickly turns vibrations into electric energy, and then into heat that is quickly dissipated. Based on the measurements, the manufacturer claims that their material possesses unique characteristics, and no other damping material can do the same thing (sadly, no direct comparison to particular materials). Damping starts faster and the vibrations have double smaller amplitude. Additionally, with conventional damping material, damping performance decreases directly proportional with the strain decrease, ultimately reaching zero. In contrast, the ‘fo.Q’ damping material shows its unique characteristic where its damping performance is inversely proportional to strain and increases with the strain decrease. The ‘fo.Q’ AB-4045R audio boards have on average 10 times the damping performance of conventional inorganic boards over the entire frequency range. In the low-frequency range (300 Hz and below) and the high-frequency range (4,000 Hz and above) in particular, the damping performance is extremely high.

This is not the first time I write about this brand’s products – previously I received a turntable sheet and stabilizer. This time I received quite a large set of anti-vibration products:

  • AB-4045R audio board (Autumn Red color; board in Sepia Black carries the symbol AB-4045S),
  • High End Damping Spacers made of fo.Q G-53FS and G-51,
  • Carbon damping spacers CS-01/CS-02 fo.Q,
  • DS-25E dampers to be used on CD,
  • cable insulators IP-11, made of special Ipe wood, heavier than water.
I was unable to test the two products – DS-25E and IP-11. DS-25E because I use a top-loader CD player with the Spider stabilizer (which doesn’t allow using those dampers), and the IP-11 because I received only 2 of them, while I would need at least 3 per channel. Hopefully, I’ll be able to review these products another time.


Recordings used during auditions (selection):

  • Bill Evans&Jim Hall, Intermodulation, Verve/Universal Music Japan, UCCV-9342, CD (2008).
  • David Sylvian, Sleepwalkers, P-Vine Records, PVCP-8790, CD (2010).
  • Denielsson/Dell/Landgren, Salzau Music On The Water, ACT Music + Vision, ACT 9445-2, CD (2006).
  • Dominic Miller, Fourth Wall, Q-rious Music, QRM 108-2, CD (2006).
  • Lars Danielsson, Mélange Bleu, ACT Music+Vision, ACT 9604-2, CD (2006).
  • Nosowska, 8, Supersam Music, SM 01, CD (2011)
  • Pink Floyd, The Wall, EMI Records/EMI Music Japan, TOCP-71142-43, 2 x CD (2011).
  • Ralf Illenberger, Red Rock Journeys, Stockfisch, SFR 357.1020.2, CD (2011).
  • The Modern Jazz Quartet, The European Concert. Volume One + Volume Two, Atlantic/East West Japan, AMCY-1186-7, K2 CD (2000).
  • Tori Amos, Boys For Pele, EastWest/Warner Music, 80696-2, CD (1996).
Japanese editions available from .

Review methodology
Usually you find this section after the „SOUND” and before the „DESIGN” sections of my reviews. But this time I think that you should read it first to properly understand my later description.
Anti-vibration accessories always work in a particular context – that of other accessories, of the mechanical design of products we use them for, of the rack under our electronics. Usually such accessories made by one manufacturer introduce similar changes, and when used in sets the changes accumulate.
That’s why when it comes to testing anti-vibration accessories I do it step by step, starting with one of them then adding one by one until I come to a full set as the manufacturer intended it to work.
In this case I started with the AB-4045R board, which bottom I fitted with 5 (4 in the corners and 1 in the center) pieces of the delivered anti-vibration material. The next step was additionally using the G-53FS spacers under my CD player’s feet. And finally I added the CS-02 spacers underneath the audio board.
After each step I compared the sound (or changes in sound) with that of my player placed on my reference Acoustic Revive RAF-48 platform. One important notice – my player is fitted (permanently) with finite elemente Ceraballs.
I did A-B-A comparisons, with A and B known, moving the player after each music sample (samples lasting 2 minutes each).
During the second test I compared the sound with the G-53FS and the G-51 spacers placed under my player’s feet, and the player seated first on the RAF-48 and then on the AB-4045R.
And last but not least I checked the influence of using the AB-4045R and the G-53FS for my Leben CS-300 XS [Custom Version], sitting on top of the Pro Audio Bono platform. The AB-4045R landed under this platform while the G-53FS under finite elemente Ceraball Slim (Leben's feet).

Ancient Audio Lektor AIR V-edition + AB-4045R + G-53FS + CS-02
The AB-4045R and the G-53FS worked in similar way, together amplifying their effect on sound. But the main, or basic element of this pair was the board – it was the AB-4045R that really “set” the direction of changes introduced by fo.Q. I found it very interesting that the changes introduces to the sound, although quite distinct, hard to ignore, repeatable, gave different effects depending on the recording – it seemed to be important how the recording was done, when, and so on. While the changes seemed to be the same each time, they revealed different characteristics of recordings depending on what I was listening to at the moment.
My CD player seated on the fo.Q AB-4045R platform sounded quieter than when placed on the Acoustic Revive RAF-48. When I played Kto? by Nosowska it sounded quieter, less energetic, slightly leaner than when placed on RAF-48. It seemed to be literally quieter by 1, maybe 1.5 dB, which I confirmed turning the volume one step up.
After some time I realized that it was not really about less energy in the sound but rather about different approach to sound presentation – more focused on what's inside particular track than on expressing that. I noticed some dynamic and timbre subtleties that were covered with that rich expression before.
The AB-4045R also caused a slight lower midrange and mid-bass roll off. At first I thought the changes were audible mostly in treble and bass but when I listened to I Should Care from The Modern Jazz Quartet album, and then to London Paris Cardiff by Dominic Miller, I realized that the first impression was wrong and that the shift of accent was more nuanced than I thought at first.

The slight roughness of Nosowska’s sibilants that could be irritating was completely gone. This roughness was not big but recognizable. My player seated on the AB-4045R played that track in a more sophisticated way. There was no sign of this slight roughness anymore. The vocal became more gentle, nicer to my ears.

It was The Modern Jazz Quartet album that convinced me that the changes introduced by the AB-4045R did not concern treble at all. Cymbals sounded strong, but also a bit soft, without the proper weight they had with the RAF-48. Bass also lost a bit of weight, comparing to the Acoustic Revive platform, and it wasn’t so energetic either.
As I already mentioned when I put the G-53FS under my player's feet the changes were similar, but the volume of changes was smaller. Sound became even gentler, smoother, and softer. It seemed that now midrange was somehow preferred, but without its richness and depth delivered with the RAF-48.

So what changes to the sound do these products introduce? After a longer period of testing I might point out some of them: upper midrange (that is a weakness of many recordings) gets a bit softer, the sound loses part of its energy, and generally becomes more gentle. But there is also a better resolution and selectivity. It’s not simply about the sound getting “leaner”; that’s not the point. When I played the piano from Tori Amos Father Lucifer, or the vibe from MJQ, I could easily tell that the attack was cleaner, more distinct although more gentle at the same time. Sound is neither bright nor coarse – it's the selectivity that improves. Direct comparison with the same player placed directly on the rack proves that with the fo.Q products the sound gets more sophisticated. But on the other hand, the sound with the RAF-48, although not so beautiful, is more energetic, richer, more palpable. Bass extends deeper and is more distinct. But then there is this upper midrange that… the AB-4045R and the G-53FS deliver in a much better way.

Compared to that, the CS-02 introduces changes of a slightly different character. I will come back to it with more details when discussing the Leben, but right now I should already mention that with the AB-4045R it was clear that the carbon dampers modify the sound towards better selectivity, clarity, while making the upper bass and the lower midrange sound leaner. With the Lektor AIR V-edition, in my system and with my personal preferences, I wasn’t really happy about these changes to the sound. But in other systems it might be exactly what you need – slightly less of the mid- and the upper bass (if there is too much of it).

Ancient Audio Lektor AIR V-edition + Acoustic Revive RAF-48 + G-53FS/G-51
The G-53FS and G-51 dampers used together with the Acoustic Revive platform introduced the same (in character) changes. Both types of isolators improve the sound’s selectivity, and it's a good thing. Without them the sound, in my system, was perfect. But when I used them I realized that selectivity could be still improved, and dynamics could be even better differentiated. And with those dampers under my player's feet that aspect of sound was clearly better; it was an obvious step forward. But I liked it more with the thicker G-53FS dampers than with the G-51s. The latter took some richness away from the sound, the richness I fought so hard to achieve in my system, until I finally succeeded. Those thicker damper added some selectivity but also some small change to the tonality, but not as significant as with the thinner dampers.
So to wrap this up – the changes introduced to the sound are clear, but not necessary welcome in each system. I am keeping the thicker dampers under my preamplifier's feet, and later I will also try them under my CD player. For here and now, the slightly leaner mid-bass out-weighted the advantages of using them. But they showed me a direction I should follow.

Leben CS-300 XS [Custom Version] + AB-4045R + G-53FS
I think that this setup really worked best in my system. Again, resolution was better and bass differentiation also improved without shifting the emphasis to the upper bass. Now I could finally hear all the improvements that the fo.Q material brings without the disadvantages described above.
When it comes to audio the main evaluation “tool” is comparison, which means that the results are relative (there is no real reference for the sound reproduced in our room; live performance can't be a real reference and it's not possible to have a perfect reproduction of live performance in any room, unfortunately…).
Therefore, I was kind of surprised after placing the AB-4045R under my PAB platform and the G-53FS under the finite elemente in my Leben when I compared the sound via the Sennheiser HD800 headphones and my speakers. I realized that what I heard from the loudspeakers was very similar to the sound delivered by the headphones. As if this nice, relaxed, very natural sound, with its physiological “warmth” that my system delivered without the fo.Q wasn't as true as I thought it was. Yes, I knew that already but I didn't care before; it wasn't important at all. Now, after what I learned during this review, I started to feel some discomfort, having some doubts.

And it is the fo.Q accessories that are “to be blamed” for that. They improve resolution and selectivity, leaving sound as detailed as it was before, without introducing any brightness or coarseness. The AB-4045R board and the G-53FS damping spacers when working together deliver more gentle, clearer sound, with a slightly rolled off upper midrange (which is good) and some bass (which might be good or not, depending on the whole system and the listener’s preferences). Changes to the sound are easily recognizable. It worked best in my headphone system, but that allowed me to see my whole system in a different, more critical way.
The CS-02 offers somewhat different changes – similar to the ones described above but supercharged, as if in a turbo mode. That's why the carbon spacers affect the sound even more.
What's very important is the fact that the fo.Q accessories are made by a professional company, deriving directly from an industrial giant, with a large R&D department. That guarantees a solid scientific basis for those products.
The accessories help you to find out weaknesses in your system, allowing you to move another step forward. As already mentioned, the G-53FS/GS-51 are especially effective while damping resonances below 300 Hz and above 4,000 Hz. The first figure was easy to confirm – in my system this sub-range sounded a bit leaner. It is possible that before using them some distortions made the sound “richer”. And my observations – improvements in selectivity and resolution seem to confirm that thesis, too.
It was more difficult to confirm or to classify the influence of the fo.Q in the range above 4,000 Hz. As already mentioned, the treble did not seem to be rolled off at all, while the upper midrange did. The way I understand and interpret that, the coarseness and brightness are caused by some distortion in the treble, by not so well delivered higher harmonics. If these are presented in a very clean fashion then the midrange also sounds much better. And the G-53FS and the GS-51 show that very clearly.


AB-4045R audio board
The AB-4045R audio board looks like a regular board. Only it is not. It is available in two color versions. It measures 450(W) × 400(D) × 20(H) mm and weights 4.2 kg. The maximum weight it can carry is 100 kg, which means that it can be used even under very heavy amplifiers, or even under loudspeakers.
The platform is a sandwich design with 3 layers: organic polymer hybrid vibration damping sheets, advanced hybrid ceramics, and wood.
Five dampers Ø75 mm, made of the fo.Q material are delivered with board. You should attach 3, 4 or all 5 of them underneath the board.

G-53FS/G-51 High End Damping Spacer
These dampers are made of the fo.Q material, which is a modified piezoelectric that quickly converts electricity to heat that can be dissipated. Both versions have the same diameter – 50 mm, but they differ with thickness and design.
The G-53FS are 1 mm thick and are made of three different polymer damping materials and a layer of fiber glass (inside). The latter is supposed to improve dampers durability under pressure. This layer also ensures asymmetry of the dampers which allows for placing them with any of the two sides up, resulting in different effects. During the review I used them with the porous side up. The G-51 are 1 mm thick and are made of a single layer of modified polymer. Dampers are delivered in a CD case in sets of four pieces.

CS-01/CS-02 Spacers
These spacers are made of a couple of layers cut out from a lacquered carbon fiber slate. Each spacer has the diameter of 24 mm and is 5 mm (CS-02) and 2.5 mm (CS-01) thick. Together with the spacers the customer receives round pieces of fo.Q (modified organic polymer) material that should be attached to the lower side of each spacer. The sets of 8 pieces are delivered in small boxes. These spacers can carry up to 100 kg, so they might be used under loudspeaker's spikes; they even have small holes drilled in the center for that purpose.


  • CD player: Ancient Audio Lektor Air V-edition, review HERE
  • Phono preamplifier: RCM Audio Sensor Prelude IC, review HERE
  • Cartridges: Miyajima Laboratory SHILABE, review HERE), Miyajima Laboratory KANSUI, review HERE
  • Preamplifier: Ayon Audio Polaris III [Signature Version] with Re-generator Power Supply
  • Power amplifier: Soulution 710
  • Integrated amplifier/headphone amplifier: Leben CS300 XS Custom Version, review HERE
  • Loudspeakers: Harbeth M40.1 Domestic, review HERE
  • Headphones: Sennheiser HD800, AKG K701, Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro; 600 Ω version, review HERE, HERE, and HERE
  • Interconnect: CD-preamp: Acrolink Mexcel 7N-DA6300 (article HERE, preamp-power amp: Acrolink 8N-A2080III Evo, review HERE
  • Speaker cable: Tara Labs Omega Onyx, review HERE
  • Power cables AC (all equipment): Acrolink Mexcel 7N-PC9300
  • Power strip: Acoustic Revive RTP-4eu ULTIMATE
  • Stand: Base; under all components
  • Resonance control: Finite Elemente Ceraball under the CD, Audio Revive RAF-48 platform under the CD and preamplifier
  • Pro Audio Bono PAB SE platform under Leben CS300 XS [Custom Version]; review HERE