WAVE KINETICS A10-U8R Audio Footer and Audio Top Weight

Wave Kinetics A10-U8R Tan Top View

How does the A10-U8R work?

The WAVE KINETICS A10-U8R vibration control device looks like nothing else in audio. It is an audio footer and audio top weight in one and while it may look odd to some, it’s performance is nothing less than remarkable. 

The A10-U8R is a revolutionary product incorporating state of the art materials and technology. Leather, being one of the materials used, has amazing vibration control properties. Later on we will discuss them more in depth. The A10-U8R has two very important abilities; it can function as an audio footer and as a top-weight.

As an audio footer, the A10-U8R is designed to provide a stable structure while still allowing for damping and vibration control. When the system is at rest, the A10-U8R behaves as a solid slug with a leather interface. The weight of the component applies force to the top of the A10-U8R which then compresses a spherical bearing array. The bearings align into a hexagonal packed structure held in place by the compliant walls of the container. The walls of the container are soft and thin providing virtually no solid path for vibration to travel from stand to component. At rest, it is as if the component is sitting on a narrow stack of very dense metal bearings with a thin compliant surface on top and bottom. There is no rigid path for vibration transfer, yet the component sits on a stable surface!

As a top weight the A10-U8R adds mass to the component’s chassis. By adding mass the component’s susceptibility to vibration is greatly reduced, but that is not really enough. It also utilizes visco elastic damping and particle impact damping.

Through the visco elastic damping mechanism energy enters and deforms a system and instead of being returned elastically, like a rubber ball being bounced, it is absorbed in viscous shear forces and dissipated in the form of heat.

Through the particle impact damping mechanism vibratory energy is removed through losses that occur during the impact of granular particles which move freely within the boundaries of a cavity attached to a primary system. The particle impact damping effectiveness is related to the ratio of the damper mass to the component mass.

Research shows that the effectiveness of particle impact damping depends, in part, on the ratio of the mass of the component to the mass of the damper. This is known as mass fraction. As a starting point, one A10-U8R would be recommended as a top weight for up to 25 lbs of mass, two for up to 50 lbs and so on.


What types of vibration are treated by the A10-U8R?

  • Mechanical vibration from component stands

Vibration energy transmitted through the floor or air introduced to the component stand will corrupt musical playback if allowed to reach the component. Sensitive mechanical components and electronics will perform more poorly in the presence of vibration. The A10-U8R greatly attenuates (-30dB ) the transfer of vibration energy from the stand to the component. There are several mechanisms responsible for this amazing attenuation.

First, the leather exterior interfaces with the extremely soft and compliant retaining structure. This causes a large impedance mismatch and reflects vibration back toward the stand. Leather is an amazingly effective vibration absorber. Elastin, a highly elastic protein arranged in a unique nano-scale structure, allows leather to return to its original shape after being distorted, stretched or vibrated. The micro-structure of cow leather is a layered, complicated network of fibers of different sizes from a few to hundreds of nano-meters in diameter. They show nonlinear stress-strain relations and visco elastic behavior. This visco elastic property is what gives human and animal skin its ability to return to its original shape after being poked or pinched. This makes leather one of nature’s finest vibration absorbing materials.  A thin layer of leather acts as a very effective vibration absorbing and transmission reducing material. The effect is easily visualized by thinking of wearing leather gloves while using a lawn mower or driving a car. In both cases, you feel an order of magnitude less vibration with the gloves on.  

Second, vibration that is transmitted through the impedance mismatch excites minute motion in the spherical bearing array. A combination of extreme density, geometry and coulumb frictional forces cause the spherical array to settle incredibly quickly. Further, the walls of the containment structure proved further damping of the bearing array. Vibration is essentially eliminated as the thousands of bearings vibrate, moving against each other creating friction losses, and react with the walls of the soft container. Finally, any vibration that makes it to the top of the bearing array must again cross a dramatic impedance mismatch before entering the component.

  • Air Borne Vibration Energy

When a component is in the same room as loudspeakers, air borne vibration strikes the component directly, bypassing the component stand. This air borne energy can excite resonances in the component chassis, and even components within the chassis. The leather exterior of the A10-U8R absorbs vibration energy across a wide frequency band helping to dissipate the energy in the chassis. Larger amplitude vibration is transmitted into the A10-U8R Vibration Control Device and is dissipated by the spherical bearing array as described above.  as well as the overall dissipation by the other materials utilized.

  • Self Generated Vibration

Even if air borne vibration and vibration transmitted from a stand is mitigated, the component itself is a source of vibration. Mechanisms inside the component such as transformers, CD transport mechanisms, reading head mechanisms, turntable motors and components, and even some circuitry can generate substantial amounts of vibration. The leather surface of the A10-U8R provides an exceptionally good interface with the component. As the component rests on the footer, the surface of the component presses into the leather creating a form fitting surface interface. This creates an effective surface area to couple the footer and component for maximum vibration attenuation. This interface serves two functions. First, it creates a path for energy to flow into the A10-U8R and be dissipated as described above. Second, the interface allows rotational energy such as nutating CD transports, and turntable mechanisms to be damped directly. For example, a CD drive mechanism may rotate at 20-30 Hz. If the drive mechanism is not perfectly balanced or if the printing on the CD is not perfectly symmetrical, the rotation will induce a vibration which will in turn shake the entire component. The soft attachment interface with the A10-U8R effectively damps this type of vibration directly. This specific mode of vibration damping was optimized for rotational and lateral vibrations as encountered in CD transports and Turntables. The A10-U8R Vibration Control Device is also effective at damping other vibration energy generated by a component.

Wave Kinetics A10-U8R Tan Low View

What are the benefits of using the A10-U8R?

The low resonant frequency of the system, the high dissipation factor of the system, and the excellent surface interface and surface damping combine synergistically to radically reduce the transmission of vibration to the component as well as absorbing vibration generated by the component itself.

By combining state of the art techniques, the WAVE KINETICS A10-U8R Vibration Control Device isolates audio components from vibration transmitted through equipment stands, and lessens the effects of air borne vibration and component-generated vibration. The effects are both measurable and audible. When placed under a state of the art SACD / CD player sitting on a state of the art rack system the A10-U8R substantially reduced harmonic distortion by greater than 75%. This translates to a dramatic improvement in sound. You will hear increased naturalness, tighter more tuneful bass, greater clarity and detail retrieval, more pinpoint accuracy and placement within the sound field, wider and deeper soundstaging with much more control especially at louder listening levels.

The A10-U8R Vibration Control Device works under a wide range of component weights. They will improve the sound of components sitting on even the best rack systems because they deal with air borne and component generated vibration – areas where rack systems are traditionally weak. Further, the use of the A10-U8R in conjunction with a mediocre rack system or even traditional furniture can work miracles. The WAVE KINETICS A10-U8R Vibration Control Device renders expensive audiophile racks completely obsolete!

Wave Kinetics A10-U8R with darTZeel LHC-208 Below

Wave Kinetics A10-U8R with darTZeel LHC-208 On Top

  • Measured greater than 75% drop in harmonic distortion
  • Dramatically shortened impulse decay response and return to system quiescence
  • Huge drop in energy transfer from stand to component (20-30 dB)
  • Dimensions:  8″ L x 3″ W x 2″ H (203 mm L x 76 mm W x 51 mm H)
  • Weight: 1.5 lbs. (.680 kgs)
  • Greater detail retrieval with increased naturalness
  • Better control at louder volumes
  • Wider and deeper soundstaging
  • More pinpoint accuracy and placement within the sound field
  • Renders expensive isolation racks completely obsolete
  • Accommodates virtually any component weight