July 2012

World Premiere!
Pro Audio Bono PAB SE AP Alu Anti-Vibration Platform
Without this kind of high quality isolation accessories we miss out on a lot of music!
Review By Wojciech Pacuła

  Reducing vibration is a fairly well-documented method of distortion reduction in electronic devices. The techniques allowing to minimize this phenomenon or, more accurately, to control it (that is, to minimize it in a controlled, predefined way) are completely normal for such demanding applications as military or medicine. In audio world, the measures to reduce this type of distortion have been known for a long time, and implemented both in turntables as well as tube amplifiers designs. With a growing popularity of the new invention which was the transistor and the later success of the CD format, eventually taking over the market, it seemed that at least this one problem was gone once for all and we could move on. After all, transistors all but eliminated microphony, while the optical reading of the signal combined with advanced read error correction mechanism in CD seemed to be ideally immune to any external influence. Well, it was true while it lasted.

For soon enough the perfectionists, i.e. audiophiles (or, as my friends says, enlightened music lovers) came to the conclusion that the mechanical design of any audio component, be that a solid state amplifier or a CD player, have significant influence on the final effect, that is sound. This in turn meant that the problem caused by vibration was not fully resolved and – perhaps – new problems were introduced which, to some extent, had been overcome in the previous generation of devices. The need to fight them gave rise to the number of manufacturers offering racks, platforms, stands, feet, spacers, cones, and many other products designed to minimize vibration.

One of such manufacturers is Pro Audio Bono (acronym PAB), located in Piaseczno near Warsaw (Warsaw, let me remind you, is the capital of Poland) and run by an engineer, Mr. WladyslawSkrzypczak (difficult name, I admit, but we the Poles just love this type of spelling conundrums...). The owner-designer's profession is important, because it shows that vibrations, resonances, their influence on sound as well as possible ways to counter them, are not the domain of madmen or stoners tripped out on weed, but rather a normal exercise in physics. Reputable manufactures confirm it with proper measurements – the Japanese excel in this, to name Acoustic Revive, fo.Q, or Audio Replas (they all actually collaborate), but VertexAQ from the UK also made remarkable progress. What they all have in common is their scientific approach to the subject matter, the fact that they employ engineers in the role of designers, and maintain close contacts with universities as well as defense and medical industry. Not to mention the measurements that accompany each of their products.

The first time I came across PAB's products was in the middle of 2010, shortly after the company's debut. I was then preparing a review of anti-vibration accessories for the Polish magazine Audio and among some very expensive components, such as a rack and accessories from the Japanese Harmonix, there was also the Pro Audio Bono isolation platform. Intrigued by its design, as well as obvious concept similarities to the racks from another manufacturer, String Suspension Concept, I invited Mr. Skrzypczak for a visit and I asked him about this and that.

Design Concept
PAB platforms are based on the idea of mechanical decoupling of two boards – the top shelf which hosts our audio component is suspended above and decoupled from the base shelf. This design concept is exactly what matters here: the two surfaces are mechanically decoupled from each other, here by means of nylon cords on which the top shelf is suspended. Of course the idea is well known and used in turntables, most notably the SME20 and SME30 from SME Limited. Their design also features two shelves, decoupled by multiple rubber rings. What is common with the PAB design is the mounting mechanism: the base shelf holds a kind of posts – four metal tubes protruding a couple of inches above the top shelf which is suspended on the rings (SME) or "strings" (PAB), attached to the top of the posts. That's all there is to it. The Polish platform design is somewhat more complex, although not by much. The "strings" are thin nylon cords, selected from among dozens of other materials. They needed to be durable, with good damping properties, and could not deform (lengthen) over time. They are not attached permanently to the posts, but rather pass through pulleys and return back down to the tensioning mechanism. Each "tensioner" is made of a machine head used for adjusting string tension in stringed musical instruments. The platform needs to be leveled and then strung so that the top shelf were as low as possible, but not in contact with the base shelf. Such is the basic PAB concept, as applied to both their anti-vibration platforms as well as speaker stands and anti-vibrations racks. It has common features with the SSC design, however it differs in many details, for as Mr. Skrzypczak says, his continuous research and measurements show the new areas for improvement.

I reviewed the first version of the PAB isolation platform in 2010; it featured thin shelves, regular feet, brass tube posts and friction bearings. Another one I bought for myself had thick shelves. After about a year Mr. Skrzypczak kindly replaced its friction bearings for rolling bearings. The newest version which is the subject of this review comes with thick shelves, roller bearings and two innovations: posts made of aluminum tube instead of brass and completely new, bearing based anti-vibration feet, replacing ordinary brass ones. This version is called PAB SE Alu AP (double plywood, large shelf, veneer, foil or paint). You can also purchase the optional PAB bearing AF feet (‘AF' stands for ‘anti-vibration foot'), which we'll have a look at as well. The feet feature self-aligning bearings in metal (brass) housing; their load capacity, depending on the version, is up to 60 kg or 120 kg (130 or 260 lbs.). Unlike other designs using rolling bearings, the innovation lies in the fact that the upper (carrier or working) part of the foot does not rest on the bearing balls, but is suspended on them (patent pending).

Test Methodology
As always, testing methodology is equally important as the test itself. My test methodology hasn't significantly changed over the past dozen years. I have improved some details but the basics have remained for they are well proven. What I do is compare the tested component with my reference component in an A/B/A comparison with A and B known, first using two minutes music samples and, in the end, full albums. I do not employ ABX tests for – as confirmed by my several years of experience during our Krakow Sonic Society meetings – they are useless in case of music and their results are inconclusive. In contrast, even short A/B comparison can show sonic differences.

A few words are due on what the ‘reference' is. The Oxford English Dictionary defines it as "denoting an object, property, value, or the like, used as a basis for comparative measurement or standardization." It also mentions "absolute reference." The former simply describes comparing two values or components, without taking into account the quality of the reference component. What is important is that it is a known value. The latter speaks of the possibly ultimate component, known and chosen because of its highest quality. In audio these two definitions are often confused.

In case of Pro Audio Bono I employed both ‘references'. The first reference was the shelf of my Base rack. The rack consists of a frame made of thick-walled metal tubes filled with oil, supporting layered shelves made of MDF and plywood, with a layer of special glue formula and Japanese paper sandwiched between the two. The shelves are decoupled from the frame with boron carbide spikes (cones) and quartz spacers, similar to RIQ-5010W spacers from Acoustic Revive. The ultimate reference for me is the Acoustic Revive RAF-48H air floating board under the Ancient Audio Lektor Air V-edition CD player and the Audio Research Ref5 SE preamplifier on the one hand, and the PAB SE AP platform under the Leben CS-300 XS [Custom Version] headphone amplifier, on the other.

Sound
PAB SE Alu AP Versus Acoustic Revive RAF-48H
My main interest was a direct comparison of the PAB platform with the Acoustic Revive RAF-48H air floating board. As it turned out, the sonic differences between them, although discernible, were however more nuanced than I'd expected, that is smaller than between the PAB platform with brass feet and the AR air floating board. Still, they were there.

The Japanese board helps the electronics to slightly better form the sound attack and to clearer present the instrument shapes. Likewise, texture differentiation, all those small characteristics together forming the ‘sonics' of the given sound source, were slightly better with the RAF-48H. The key word however being slightly. For the Japanese platform is actually much more expensive, requires periodic inflating and is a true reference. The differences were not so much structural, as both platforms shape the sound in a similar way, but rather superficial, as if the same base framework was filled in each case with slightly different content.

But the differences were there. The Polish platform somewhat rounds the treble, withdrawing it gently. It was audible with Sara K.'s vocal on her solo concert CD Don't I Know You from Somewhere? [Stockfisch SFR 357.6055.2]. On this album she accompanies herself on a special, four-string guitar. Typically for Stockfisch, the recording is outstanding but there are still some limitations inherent to live concert production. One of them is a slight accentuation of the sibilants, forced I think by the particular stage microphone choice. It is not irritating or particularly disrupting but with the RAF-48H we know where it comes from, what could be its origin, and we take it together with "the whole package." The PAB board smoothed out this sub-range. The microphone sonic signature was not as well audible as before. But, to put it into perspective: the difference was minor, more of a slight shift of accentuation than a significant alteration. Correspondingly, it was also noticeable with electronic music, for example the remixes of the track "Personal Jesus" by Depeche Mode [Mute, CDBONG43]. Here, additionally appeared a small warming up of sound, not so apparent earlier.

However, there was an area where the Polish platform fared better – midbass control. Both isolation boards show exemplary bass range. Stiff, mass market racks and shelves usually thin up the sound in the bottom end, taking something away with it. They give instead precision and timing but, I think, only because there is less to control, not that they bring some real improvement. In this respect – again, in my opinion – "springy" boards come up on top. Both platforms are top-notch contenders. Still, the PAB platform brings something extra, i.e. it shows the midbass with more precision, without any thinning up or drying up. This is the double bass sonic range, and the improvement was evident for example on the "After Hours" album by André Previn, newly remastered by Winston Ma for his First Impression Music record label (Lasting Impression Music, LIM UHD 051; these are re-editions of Telarc CDs and this particular album cover features a reproduction of the award from High Fidelity magazine, where I am the chief editor – so why I shouldn't mention it...). Likewise, Joe Pass's acoustic guitar seemed more focused, not (slightly) sloppy as before.

PAB SE Alu AP Versus Nothing
Having listened to music for several years with my CD player sitting on the Acoustic Revive isolation board (first the RAF-48, currently the RAF-48H) and with the PAB SE AP platform under my Leben CS-300 XS Custom Version headphone amplifier, I have apparently forgotten what these components bring to my system. From time to time, reviewing other isolation boards I am suddenly made acutely aware of that fact, but the rest of time I live in blissful ignorance, taking THIS sound for granted, as my reference sound.

A quick comparison of the PAB platform with the audio components sitting straight on the rack shelf, with no isolation board whatsoever, was more than enough to make me shout loud and clear: without this kind of high quality isolation accessories we miss out on a lot of music! And yet my rack is nothing to sneeze at; thick-walled tube frame made of special steel, filled with oil, custom shelves made of sandwiched MDF and plywood, decoupled with quartz spacers… But I cannot turn the blind eye (or rather ear) to what I hear: the PAB platform, similarly to the AR, brings a lot of life to music.

For the fact that both platforms change the sonics, lowering it, that they eliminate the tremor of the top end correcting its overly bright character, which they make the bass full-bodied with nice texture – these are all important improvements but not as vital as something that is more general in nature. With this particular version of the PAB platform, that is one with thick shelves, bearing based suspension and aluminum feet we get a much better colored, a much more "muscular" presentation. Take the platform away and the sound seems anemic and withdrawn. I know that such sharp differentiation disappears over time and sitting our audio components directly on the rack shelves and living with that sound, we eventually get used to it. Still however, sitting the CD player or our preamp back on the isolation board turns everything upside down, as if some kind of window re-opened in our mind.

It is a very fleshy but well controlled sound. Remarkably vital in the sense that it is agile, never sounding lazy. Lower mids and the midrange in general are accentuated while the treble is slightly warmed up. Not to the extent that it masks anything – when the orchestra breaks in on the new "Valtari" album by SigurRós [EMI Records Limited 6235552] it sounds big, full, unmuffled. Similarly, when the drums enter on the 301 album by e.s.t. [ACT 9029-2], the cymbals are resonant and have proper weight.

PAB Bearing AF Versus Classic Feet
Finally, a few words on the sonic difference between classic feet and the PAB bearing AF feet. As with any mechanical change, this one also has influence on sound. The improved PAB feet open up the sound, helping to show deeper sound stage. The differences are not as marked as those between the PAB platform and a typical rack shelf, but they are nevertheless positive and evident. The excellent timbre and texture remain, with added ‘breath', or ‘air'. It's well worth trying!

Conclusion
In the end, no longer can you live without a good isolation platform. It brings the most marked improvement in case of digital players, including network audio players (sic!), followed by preamplifiers, and finally power and integrated amplifiers – no matter whether tube or solid state. It has a cumulative effect, i.e. positive changes in individual components of the hi-fi chain all add up and the improvements accumulate. It is unequivocally a good direction and I for one cannot imagine listening to music without good platforms. Whether it be the very expensive Acoustic Revive board or the astronomically priced Harmonix system, the choice is all yours. But even if you are not fully convinced at this point or you simply like experimenting, you need to try out the newest version of the Pro Audio Bono platform; you will be in for a surprise how much your system's sound can be improved for a comparatively modest price. That remains true not only for the fat components worth $5000 to $10,000 but also those modest $500 pieces – you have my word for it!

Specifications
Type: Decoupled anti-vibration platform for audio components.
Dimensions: 560 x 400 x 175 (WxDxH in mm, total)
                   480 x 400 (WxD in mm, top shelf)
Weight: 26 lbs.
Price (in Poland, in Polish Zloty=PLN; 1 PLN=3,35 USD): 2,400 PLN (approximately $700) with metal feet; 3,200 – 3,800 PLN ($1,100 at most) with bearing based feet (the price difference reflects the feet housing size – its height and diameter as well as the type of bearings (rolling, self-aligning, angular).

Company Information
Pro Audio Bono
ul.PolnychKwiatów 21/1
05-500 Piaseczno/Mysiadło
Poland

Voice: +48 602 243 758 or +48 795 148 694
E-mail: biuro@proaudiobono.pl
Website: www.ProAudioBono.pl