Vibrations induced from loudspeakers can turn the surfaces of a room into unwanted sound radiating sources. Vibrations can also induce noise in the output of sensitive electronics such as turntables due to the phenomenon of microphony.
The patent pending design of our Carbide Base audio isolation feet isolates these vibrations in all directions when placed under your audio electronics and loudspeakers.
Separate upper and lower portions are designed to optimize vibration isolation and dissipation in vertical and horizontal directions.
The upper portion is machined out of aluminum billet 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 comprises separate machined stainless steel sections. 18 zirconia ball bearings and 3 viscoelastic elements are incorporated to enhance horizontal isolation and damping. The bottom is threaded to facilitate nearly 3/4″ (20 mm) of height adjustment. It can also optionally accept the 3 provided spikes to pierce through carpet.
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 elastomer isolators. The low shape factor is made possible by the patent pending design of the Carbide Base footer. Ridges selectively brace the ViscoRing™ to stabilize it under compression and shear while leaving a substantial surface area free to bulge.
Carbide Base footers can be optionally mounted to equipment and loudspeakers with the supplied screws in metric thread sizes M4, M6, M8, M10 and imperial sizes #8-32, 1/4″-20, 3/8″-16, 1/2″-13. The screws are standard flat head machine screws allowing easy substitution for a different thread size or length. A removable nylon insert is provided for smaller diameter screws.
A machined stainless steel jam bolt is provided to thread in behind the screw to secure it in place. The jam bolt can also be removed to provide a cavity to captively hold a loudspeaker floor spike.
"Carbide Bases not only turned my DAC into a gutsier and rounder version of itself, but also faster and dynamically more gifted on top of that. This sensibly more elastic, orderly and optically grander outcome was quite the surprise for me."
"Bass cleaned up even more, my small knots of structural striations vanished and floor-borne involvement felt eradicated. On a good day I'd expected that, just not this much. What came as a shock? The entire system's noise floor seemed to have fallen."
All Carbide Base footers are the same size. Each is optimized for the weight of your equipment by choosing among the 4 available interchangeable ViscoRings™. The recommended supporting weight range with each ViscoRing™ installed is shown below.
While some isolation devices require different versions for different weights, a single version of the Carbide Base footer can support a wide range of equipment weights by simply replacing the installed ViscoRing™.
Conventional floor spikes under loudspeakers transmit a significant amount of vibration energy into the floor throughout the bass and midrange frequencies. Many traditional vibration isolation devices will provide isolation at higher frequencies but exhibit an amplification of vibrations in the lower frequencies near the resonance frequency of the device.
The Carbide Base footer is unique among audio footers in its ability to effectively both isolate and damp the lowest audible frequencies. Low frequencies are important to isolate as they travel with little impedance throughout the room and equipment, degrading audio fidelity along the way. The reduction of these structure-borne vibrations improves midrange clarity and bass extension by reducing the masking effect brought on by room structure noise. The general reduction in noise provides equally important improvements in the high frequencies.
Vibration energy transmitted from a 2-way loudspeaker into a 32 kg (70 lbs) aluminum plate placed on top of the loudspeaker. The measurements were taken with the plate sitting on 4 floor spikes and then with the plate sitting on 4 Carbide Base footers with medium ViscoRings™. Acceleration was measured simultaneously in horizontal and vertical directions with a ACH-01 sensor, 10 dB gain, using 30 to 1000 Hz log swept sine excitation.
Loss factor, or tangent delta, is a measure how much vibration energy is dissipated through a conversion to heat due to the phenomenon of hysteresis. A loss factor of 0 indicates a perfectly elastic material where the oscillating force of a vibration occurs in-phase (at the same time) with the accompanying deformation of the material. A loss factor of 1 indicates a perfectly viscous material where the force and deformation are exactly 90 degrees out of phase resulting in total dissipation of vibration energy to heat.
The viscoelastic materials utilized in Carbide Base footers are engineered to have an exceptionally high loss factor over a wide frequency range. The gray ViscoRing™ has the highest loss factor, followed closely by the blue, black, and red ViscoRings™ which can support incrementally higher weights. For reference, natural rubber has a loss factor of about 0.05 across most audible frequencies.
The vibration dissipation ability of a Carbide Base footer is significant enough to measurably subdue resonances in equipment being supported. The graphs below show low frequency vibrations in the panels of a test loudspeaker enclosure as measured using a calibrated accelerometer. Dips and spikes in panel acceleration indicating resonances are effectively damped when the same measurement is taken with Carbide Base footers placed under the loudspeaker.
Loudspeaker panel acceleration measured with a ACH-01 sensor, 10 dB gain, using 35 to 150 Hz log swept sine excitation. The measurements on Carbide Base footers are shown in blue. The measurements on floor spikes directly on the concrete floor are shown in red. See the Vibration Dissipation Measurements for details.
1 Insert supplied 2.5mm Allen wrench down into each of the 3 holes on the top pad and unscrew the bolts housed within. Note: Once fully unscrewed the bolts will remain retained under the pad.
2 Pry apart the upper and lower portions to access the installed ViscoRing™. Be patient prying apart as the ViscoRing™ can become tacky and slow to separate. The bottom portion can be partially unthreaded to increase prying leverage.
3 Replace the ViscoRing™. Ensure that the new ViscoRing™ is fully seated into the underside of the upper portion. Store the unused ViscoRing™ in a safe place. It is normal for newly installed ViscoRings™ to settle and compress slightly after an initial period of use.
4 Align the top holes on the upper portion with the thread holes on top of the lower portion. Press the upper portion down over the top of the lower portion.
5 Insert the Allen wrench into the top holes and tighten the bolts housed within. The bolt will stop turning when fully secured. Do not overtighten. Pressing down and lightly twisting the upper portion can help guide the bolts into their holes. If the bolts still do not align with their holes, remove the upper portion and try again.
6 (Optional) Unthread the bottom section as needed to increase the height of the Carbide Base< footer to level uneven loads.
