This review page is supported in part by the sponsor whose ad is displayed above
Reviewers: Marja Vanderloo & Henk Boot
Sources: Acoustic Signature Mambo, Acoustic Signature Final Tool MkII, Kuzma Stogi, Benz Micro Glider
Preamp/integrated: Acoustic Signature Tango phonostage, TacT RCS 2.0 room control system; Audio Note Meishu, modified, with AVVT and KR Audio 300B output tubes
Speakers: Avantgarde Acoustic Duo, internally wired with silver; Audio Note AN/Jsp, silver wired
Cables: Audio Note AN/Vx interconnects; Siltech Paris interconnects; Gizmo silver interconnect; Qunex 75 reference interconnect [in for review]; Crystal Cable CrystalConnect Reference interconnect, CrystalDigit S/PDIF RCA/RCA and RCA/BNC, CrystalSpeak Reference, CrystalPower Reference AC-Eur/IEC [in for review]; Gizmo silver LS cable
Power line conditioning: Omtec PowerControllers
Sundry accessories: IAR carbon CD damper; Denson CD demagnetizer; TacT RCS calibrated microphone and software; Exact Audio Copy software; Compaq server w/Windows Server 2003 and XP; wood, brass and aluminum cones and pyramids; Gizmo's Harley Davidson cap; silver Buddha head
Review Component Retail: $190
We were preparing a review of a complete system -- digital/analog front-end, preamp and power amps -- when Austin Jackson's e-mail of Boston Audio Design arrived. He asked whether we'd consider auditioning his Mat 1 with the Acoustic Signature Mambo turntable that was already part of our review set. This intrigued us so we accepted. Just a few days later, the parcel service delivered a box containing the Mat 1.
In the meantime, we researched this unknown device and found Boston Audio Design's website quite informative. A white paper there states that while a stylus is reading the groove with its millions of tiny bumps and ridges, some of that mechanical energy picked up by the stylus is reflected back into the vinyl itself. It sets up a mechanical feedback loop between pickup and carrier. This vibrational exchange interferes with the raw data retrieval to introduce smear and a loss of detail, clarity and immediacy.
According to this view, the challenge is thus to cancel the reflected energy via absorption. Whatever energy the undulating movement of the stylus atop the spinning record creates should somehow be captured or attenuated to prevent it from feeding back into the stylus.
The most common address to capture this energy deflection is to make the turntable platter from a material that is absorptive in the first place. This becomes an energy sink not only for stylus resonance but vibrations that are set up by other moving parts such as the main motor. Therein lies another challenge. It is not easy to design a platter that isn't overdamped to result in a sound as dead as the platter itself. Accordingly, some intermediate half'n'half solution is often applied, with a platter that isn't completely inert and thus still prone to reflect a certain amount of stylus vibration back into the cartridge. Now felt mats are added between platter and record to become an intermediate absorptive layer.
Felt is not ideal but its low mass and other properties make it quite "musical" by avoiding overdamping effects in the audible frequency range. Other solutions somewhat elevate and suspend the record above the actual platter to now render it prone to airborne vibrations. Then there are foam or fiber mats said to incur subtle changes in frequency response or timbre. No matter what is tried that might seem like a satisfactory solution at first, long-term listening could remain unconvincing.
If the need for a mat seems obvious, the question about what material to use arises next. The mat's task is twofold - absorb stylus reflections and decouple the vinyl slab from platter-borne vibrations. Boston Audio Design's solution is pure carbon in the form of graphite: "Graphite has a molecular structure of loosely coupled sheets of hexagonally arranged carbon atoms - an ideal material for dissipating the kinds of low-level vibration present in audio equipment. The loose coupling of the sheets of atoms is also the basis why graphite is such an ideal lubricant. The graphite used in the mat is synthetic. This offers very high purity compared to most natural graphites and is good for making intricate parts. Of course, this kind of synthetic graphite is not 100% pure since different recipes are used to get different mechanical properties. Moreover, naturally occurring graphite is not 100% pure either and is typically far less pure (meaning its pure carbon content) than synthetic counterparts.
Many publications use the term carbon-graphite. This is partly caused by Stereophile's Michael Fremer when he referred to the graphite mat on his Simon Yorke turntable. He wanted to emphasize that the mat in question was not made from carbon fiber, that very common material many tennis rackets and golf clubs are made of nowadays. Unfortunately, carbon-graphite is in fact a very specialized material made by sintering carbon and graphite with tar pitch to create a very compression-resistant material. This true carbon-graphite is not suitable for audio purposes."
The Mat 1 is made of the same stuff you find in your lead pencil (talk about confusing names - where's the lead in your pencil?) The use of a carbon-based material for audio use is not surprising. Austrian luthier Dieter Ennemoser has worked for many years on his C37 theory wherein he combines a major building material of the human body and the inner ear in particular -- carbon -- with the body's core temperature of 37 degrees Celsius.
In working on the mat, Austin Jackson made prototypes from over a dozen grades of graphite from various vendor sources. Since most all synthetic graphite is 99+% pure carbon (natural graphite variants may be as low as 80% carbon), the remaining differences deal with particle sizes and how the layers are bound together. These variants all sounded different. Austin narrowed it down to two or three final contenders, sent those mats to audio industry friends and performed his own listening tests with his Linn LP12. The final grade chosen offered the most consistent benefits with a wide variety of tables.
Since the graphite component of the Mat 1 is partially what's in a lead pencil, an untreated Mat 1 could literally be used for drawing pictures on paper. It is thus necessary to seal the Mat 1 and prevent particle loss while whatever is used as sealant should not interfere with the painstakingly sought-after sonic qualities of the synthetic graphite in the first place.
|The production process of a Mat 1 begins with a raw slice off a rod of carbon-graphite of the desired quality. The rough slice is then trimmed to the requisite diameter after which an inner recess for the LP label is trimmed out. After the machining process, both sides of the mat are polished at 4000rpm high speed. All of these steps are computer controlled. Only a CNC machine can work to the minute tolerances required. The final step is the proprietary sealant applied in four successive ultra thin coats. It does change the Mat 1's sound - for the better according to Jackson who performed blind testing with a listening panel.
After this entire process, one Mat 1 arrived in Rotterdam. It felt cold in our hands when we removed it from its box. The next handling sensation was one of smoothness, albeit not like a glass platter. The Mat 1 has tiny openings in its surface. When taking a closer look, the dark silvery gray disk revealed tiny black specks of porosity all over. We put the Mat 1 aside and prepared the Acoustic Signature Mambo, a very heavy and solid turntable. An external motor drives its 5cm tall platter with a belt. The base of the turntable is 6cm thick and sits on three adjustable feet. Altogether, the Mambo displaces more than 30 kilos on a scale. This table arrived with its own felt mat.
Having a turntable in-house after many long years without one was a real joy. From the basement, we dug up our vinyl leftovers from decades ago that somehow survived our Martha Stewart-reminiscent uncluttering projects. Only a few of these records are of more recent vintage, say Dead Can Dance's Toward the Within. The rest is a bleak condensation of what once was an extensive collection of '70s jazz and progressive rock. In addition, the filched collection hides the odd classical album. What is significant, however, is that most LPs are safely tucked away in Nagaoka inner sleeves.
When the first record rested on the felt mat and the Benz Micro Glider's needle on the Kuzma Stogi arm lowered into the outer groove, tears welled up in our eyes not only because of the sound produced but because of all the images associated with this forgotten music. Music is such a strong container for memories. In the glow of this cloud filled with memories, a good handful of albums passed under the tiny needle. Having to get up every 15 to 20 minutes added a special connection with the music played. Handling the large paper sleeves -- many of which had lost the bonding capacity of the glue -- and being able to read the liner notes without bifocals too was special.
When the first emotional rush receded and the other side of our brains kicked in, certain negatives about this particular LP/record player combination reared their head. With the ear/brain now in critical mode, we revisited a number of albums. Here and there, especially during dynamic parts, the sound tended to compact with sharp overtones. These LPs had seen some rough times and weren't squeaky clean. Time for tweaks.
From the forgotten crates of black vinyl emerged a Hi-Fi News Analogue Test record. That was good news! With the help of this LP, we could adjust the Mambo to accept the extra 3 mm thickness of the Boston Audio Design sliver.
Time for the Mat 1. When we attempted to remove it from its resting place on a side table for action, it was stuck. Due to the meticulous polishing applied to this graphite disk, it created a vacuum between the table surface and itself. It took time and very careful prying to get it off. With the Mat 1 finally on the Mambo's platter, we played the same choice albums again. The first observation became enhanced focus, improved overall coherence. Next, it seemed as though someone had cleaned the records of dust and grime from years of abuse. We felt lucky that our old cartridge had been a budget job with a relative thick stylus. The Benz Micro now easily dove deeper into the grooves to overlook the more worn higher parts. Even though the sound mimicked a cleaned record, the stylus itself dug up zero dirt from the groove. The conclusion had to be that the improved background silence with the Mat 1 was the result of minimized groove echo that Austin Jackson describes in his white paper.
Many more records followed. This experience repeated itself. The Mat 1 cleaned up the sound and attenuated self noise which no longer overlaid the music. The result was a more defined musical image. Moreover, with the noise gone, the whole sensory experience became far more relaxed. With thousands of CDs in our drawers, this analogue quality came as quite a blow. Had we been missing out so much throughout the intervening vinyl-starved years? Had we been complete fools to give away and sell large amounts of black gold to occasionally actually replace them with CDs? Yes and no. We try to hold on to the "No!" and rationalize that had we stuck exclusively to vinyl, we would never have discovered so many new styles of music. Very little so-called world music is released on vinyl, for example. (Precisely and the only reason why I have never embraced the format; it doesn't serve my musical tastes - Ed.)
|For a couple of weeks, the Mat 1 improved on the Mambo. Then it came time for the entire system which the Mambo was part of to return to its owners. We now asked the same distributor to bring over another turntable while he picked up the review loaner, something he was more than willing to do. Additionally, he brought with him an Okki Nokki + record washing fluid.
Behind the name Okki Nokki hides a Cadence vacuum record-cleaning machine that sucks off the washing fluids and whatever dirt those loosened from the grooves. The result is a very clean record than can subsequently be treated with a preservative while still on the Okki Nokki's platter.
We set the new Acoustic Signature Final Tool MKII table with Rega arm and again a Benz Micro Glider on a shelf that was supported by four Solid Tech feet of silence spring-loaded footers capable of supporting the table's 30 kilos. The Benz Micro Glider's output fed to an Acoustic Signature Tango phono preamp, then our trusty Audio Note Meishu outfitted with a pair or Czech KR Audio 300Bs.
|The Final Tool MKII with this arm does not allow for VTA|
|adjustments. Nevertheless, we put the Mat 1 on its platter and cued up the Hi-Fi News test record for starters. Not one of its tracks revealed any loss of high frequencies or muffling that can be indicative of a wrong VTA when a record or mat is too thick.
Now using our own reference electronics in the chain, the differences to the prior loaner rig -- highly digital and solid-statish -- were so enormous that we had to reestablish a base line. Off went the Mat 1, on went our standard felt mat, with all records to be used for this test Okki Nokki'd first. Many consider doing dishes a chore. Doing records is straightforward fun. Just look at those shining black beauties!
|After considerable listening and enjoying the rediscovered analogue treasure pleasures from the basement on the felt mat, the Mat 1 re-entered the picture. From the first tone of Keith Jarrett's piano from The Köln Concert, it hit us. What had happened in combination with the more solid-state prior set and the same cartridge seemed now even more pronounced. To call it an effect in this context is not the right expression. Comprehensive cleanup is more like it. The Mat 1 subtracted all the background noise that interfered with the audible difference between sound and music. This mat does not act as a filter. No data are removed, no sounds or timbres are altered - yet the difference between felt mat and Mat 1 was huge. Even though the two Acoustic Signature tables employ massive and very heavy aluminum platters that would seem to create effective barriers against external|
|interferences reaching the cartridge-LP combination, these interferences -- which must be positively minuscule by comparison to foot falls -- are clearly not as well neutralized as with the Mat 1 in place.
Our conclusion at this stage is that with heavy weight platters, the Mat 1 reduces or outright prevents groove echo from finding its way back into the musical signal through the pickup. A far purer signal is the result. And that equals purer music. The Mat 1 subtracts reminders of mechanical artifice from the tunes.
Living with turntables again, rediscovering some gems in our basement and becoming acquainted with the difference the Mat 1 made to these records has made a great impact on our audiophile perceptions. In the coming months, we will revisit the workings of the Mat 1 on other turntables, notable those with less massive platters. From what we anticipate based on our present experiences, the Mat 1 should make a substantial difference on those turntables as well. For now, it should be clear that we're quite blown away by Austin Jackson's deceptively simple device that does far more than its modest appearance would suggest - until you've given it a spin, that is...
Would you like to download the current image?