What's under your turntable...! Q: What holds your turntable? A: Hopefully, it's not the top surface of a loudspeaker, or that you've got it on top of your receiver/amplifier......or any device that creates electro-magnetic fields, or vibrates when powered up. The turntable is sensitive to its environment. Here's what's at play: In the groove it's a physical imprint of an acoustic waveform. The platter spins the record at (we hope) precisely 33-1/3rd rpm. The stylus traces the terrain of the groove, wiggling a cantilever about its pivot. If moving magnet - cantilever wiggles the magnet near to coils of wire. If moving coil - cantilever wiggles a criss-cross of coils within the magnetic field of a powerful magnet. Electro-magnetic induction produces a voltage in the same waveform of the groove modulations tracked. This current is tiny. Measured in milli-volts (symbol: mV, 1 mV = .001 volts ) it can be as low as .13 mV for a low output moving coil, or from 2.5mV to7mV if moving magnet. Moving iron output is similar to moving magnet output. In whichever case it's a tiny signal generated through electro-magnetic induction - as the diamond stylus - too small to be seen without a microscope - traces a comparatively sized modulated groove. Such a fragile and tiny electric signal can be corrupted by forces from within the turntable and by external airborne forces from without.* The signal can be dirtied with the noise of vibrations coming up through the platter and mat holding the Lp. The signal can be corrupted, even destroyed by airborne sound waves bombarding the phonograph cartridge from above. The induction signal generation going on in the cartridge can be corrupted by nearby electromagnetic fields. We want to make sure it's not one of the other audio components. *(we might also look into tone arm wiring at this point, but the page is about turntable support, not wires.) So the thing is sensitive to its environment. The page means to explore the various methods, tools and products that can reduce these performance polluting processes as noted above through the use of turntable stands as well as special turntable footers that can mitigate or even eliminate surface borne vibration and help isolate from airborne sound waves. Define and identify the forces at play. Surface borne vibrations are generated by the turntable itself. Some designs of turntables have a platter drive process that generates more vibrations than do others. For instance idler driven turntables tend to produce higher levels of drive train vibrations than do belt drive or direct drive models. It is possible to mitigate this somewhat through plinth and cabinetry design. Methods of vibration dampening for idler driven turntables can be found elsewhere in pages devoted to plinth design. This page is about 'what's under' your turntable.. External surface borne vibrations flow into the turntable through the furniture that supports it. If the turntable sits atop an audio component rack holding several system components, the combined vibrations of all the components might be traveling up and down throughout the rack. Just a possibility one might think about. Loud-speaker generated airborne sound waves can attack the stylus/groove interface from above in subtle or not-so-subtle ways. Loud speaker generated sound waves can travel through solid materials to enter your turntable. Seismic: a word that implies floor shaking or the Earth in motion. Footfall: Webster's says it's the sound of a footstep. In audio, footfall is something more than just the sound of a footstep. Also implied is the impact a footstep has upon the floor in the room. Imagine you have your LP-12 up on top of a nice and not-inexpensive component rack playing a record. All might be well but with every step you take, the floor ripples under the load/impact of your foot. The seismic ripple flows through the flooring to your audio rack and shakes it. Up on top of the rack the effect is more like a teeter motion that tilts the rack this way and that in tiny sharp jerky motions. The turntable shakes. The stylus in the groove might even jump out of the groove from this violent disturbance. And it's a reality in modern home architecture. The suspended floor. Some buildings and houses have flexible flooring, others are more solid and less susceptible to the seismic ripple effects of footfall. Ideally, the turntable needs be held absolutely motionless. Perfectly still. That's a fairly tall order since the ground upon which we build our homes is in constant motion. I read somewhere that the Earth itself vibrates at around 3 hz (cycles per second). All by itself! Then, in addition, if you live in the city and next to a street, the traffic going up and down your street can produce vibrations that flow through your home...and into your turntable. But that's life living next to traffic. Quieter ground can be found. Perhaps the building you are in and indeed the very land it stands upon will provide your turntable with the best of all upgrades...or it might provide it with additional challenges to be overcome. Acoustic considerations, Room shape. Proximity to a speaker. Proximity to room corners. Room treatments. Yes but this is about support hardware, some of which can mitigate the effects of acoustic feedback. In every case, the turntable is sensitive to its environment. With all the above in mind, what lies below are the various methods, past and present, that have been put into use so that a turntable might silently rotate its platter in the ideal unperturbed state. Mounting methods are categorized as follows:

Floor standing, with or without suspension wall mounted, with or without suspension suspended from the ceiling. So far there is only anecdotal evidence of this method ...and those stories might be coming from the minds of aging hippies, I suspect.

Additionally, various isolation methods may be employed in an effort to insulate/isolate the turntable from its environment as follows:

suspension via springs, elastic belts, tennis balls, opposing magnets, pneumatics, hydraulics Active Base (computer control) or Passive Base (mechanical control) resonant energy sinks (example: sand box) constrained layer shelving high mass plate shelves such as 2 inch thick slate cone footers, mounting pucks, roller ball isolators, etc. rubber feet typical in a vintage oem setup. (replacements are available off the shelf in a variety of sizes and shapes)

Feet and devices under the turntable plinth This purpose should seem obvious but there's more to it when you consider the possibilities of isolation that are available; Isolation from the ingress of surface borne vibration and Isolation from the aerial bombardment of acoustic feedback. That much said rubber feet are a logical choice. Rubber feet kind'a grip the surface and hold the table firmly upright. Rubber feet damp some of the vibrations happening on either end of the foot. And they don't cost much. Materials that might be used in feet:

Felt Cork Rubber Sorborthane Silicone Steel Brass/bronze Aluminum Ceramic Carbon Fiber Unobtanium ...... ;^)

Pads as a footer made from soft vibration dampening materials. Bright Star Audio IsoNode anti-vibration feet. "The most cost effective upgrade in the industry!" (quoted from the bright star audio web page) link: https://brightstaraudio.com Woodland Hills California Herbies Audio Lab for Tenderfeet, Baby booties, Hi-End Booster Base, the Soft Fat Dot and much more. https://herbiesaudiolab.com/collections/component-isolation based in Selma, Texas USA Mapleshade ISO Blocks https://mapleshadestore.com Maryland, USA Elastic Rings can be used to construct a spring system ISONOE ISOLATION SYSTEM Made in the UK Applications: Home audio and Night Clubs (DJ use), Scientific Industrial hint: click on thumbnail to view image full size. Below, a quote from the company "The Isonoe Isolation System is available in packs of 4 isolation feet. Since release in 2004, Isonoe Isolation System has been proven effective at blocking the transmission of vibration in a diverse array of applications, from classic turntables and valve amplifiers, to scientific apparatus outside of the audio sphere such as that found in photospectroscopy and bio-cellular laboratories. In the case of turntables, the ability to prevent feedback in high -SPL- environments has enabled the isolation feet to become an industry stardard within nightclubs." Link to the company website: http://www.isonoe.com hint: click on thumbnail to view image full size. Pneumatic Syspension (air) Pneuance Audio http://www.pneuance.com Made in USA Applications: Audio Pneumatic foot pods called "PNEUPOD". The Pneupod uses a rubber diaphragm inflated with air pressure to isolate what it holds above from that which is below. More info at the above link. More photos below. hint: click on thumbnail to view image full size. Magnetic Levitation Feet: Opposing magnets repel. click on thumbnail to view image full size Clearaudio Magix²: Magnetic levitation isolation feet. https://www.gcaudio.com/products/clearaudio-magix-magnetic-levitation-isolation-feet/ Above link to GC Audio who lists this product as available by Special Order Only. Used sets at Ebay, Agon, Canuck AudioMart and US AudioMart, etc Hard Cones: What's the deal with cones! They don't isolate, they couple. Surfaces above and below now have a point of entry to do the cha-cha with each other. . A typical use would be in combination with a dedicated energy-dissipating shelf. The idea being to direct the vibe energy from the turntable into the energy-dissipating-shelf upon which it stands, while not allowing vibes coming up from the supporting structure to enter into the plinth of the turntable. The notion seems to be full of hope. I'd want some measurable evidence to know if it's working. Cone Feet and pucks in Carbon Fiber: Black Diamond Racing https://www.bdrsound.com Cone Feet in Ceramic DH Labs Golden Sound -- DH Cones photos are from the webmaster's personal "Large" set. web site: https://www.goldensound.com/ Here's a quote from the Golden Sound DH Cones web page: /quote "DH Cones are ceramic stands which enhance your audio system by minimizing sound vibrations and distortions to your stereo equipment. DH cones are made of high-tech ceramic material, often used in space shuttles and advanced military rockets. They have a hardness degree of 9.5, surpassed only by diamonds. Their design is based on the theory that the ability of materials to minimize vibrations and resonance is correlated to the hardness of the materials. snip..... DH Squares are Graphite-based composite squares that will reduce vibration of your components. The most effective way to use them is to place them under DH Cones. Since DH Squares will help disperse vibration much faster than normal material, they will boost the performance of DH Cones by 50%." \end quote Mapleshade Brass Footers for speakers and electronics https://mapleshadestore.com based in Maryland, USA Mod Squad Tip-Toes : Solid aluminum. Hard Cone feet. This is one of the early cone footers to be offered commercially as an audio component accessory and it dates back to the 1980's. VIBRAPOD Isolators and Cones Web: http://www.vibrapod.com St. Louis, MO, USA Stillpoints: Cone Feet with internal array of ceramic bearing balls designed to dissipate vibrations coming from above and below. hint: click on thumbnail to view image full size https://www.stillpoints.us Wisconsin, USA Symposium ROLLERBLOCK These allow horizontal motion while being constrained by the concave curvature of the cup in combination with gravity. This freedom of motion in the horizontal offers some isolation from seismic motion such as foot-fall. Vibration energy dissipation is implied by the mfr. See also Symposium shelf systems noted elsewhere on this page. https://www.symposiumusa.com Wayne, NJ, USA Coil Springs Townshend Seismic Load Cell: Compression (coil) spring surrounded by a flexible synthetic rubber jacket with two end plates. This is the building block of their current line of isolation shelves and equipment rack systems. hint: click on thumbnail to view image full size. http://www.townshendaudio.com UK based ---Isolation Shelves, Platforms and Bases--- To isolate from surface borne vibrations coming up from below the component Shock Absorbing Frame for the EMT 927 and EMT 930 Application: Commercial Broadcasting and Home Audio. passive. EMT owners tend to state that the base is generally useful on light springy floors and does isolate from footfall. However they will quickly say that there is no other audible benefit. I think these shock absorbing frames look really cool in an industrial context. hint:click on thumbnail to view image full size. Available for sale here: https://www.g-t-i.de/page.php?lang=en&page=frame based at Lahr, Germany Ginko Designs: A platform/base that provides Isolation by means of soft springy Squash Balls between upper and lower plates. Applications: Hi-Fi http://www.ginkoaudio.com Piezo-Electric Active Isolation bases, shelves and platforms Halcyonics Active Vibration Isolation web: https://www.halcyonics.com some of the applications:

microscopy (numerous vibration-sensitive applications) scanning electron microscope optical 3d measurement profilometry custom applications

headquarters: Goettingen, Germany North America: Accurion, Inc. web: https://www.accurion.com Piezo-Electric Active Isolation Bases, shelves and platforms. Herzan TS series : web: http://www.herzan.com (no air) sub herz active vibration isolation across 6 degrees of freedom piezo-electric Applications: Industrial

SPM (AFM,STM, NSNOM, etc) High Precision Metrology Interferometry Fluorescence Microscopy High Resolution Microscopy Profilometry In-Vetro Fertilization

Headquarters: Switzerland Negative Stiffness: Minus-K : Minus K Technology BM-8 platform shown supporting a Simon York S7 turntable. This platform boasts passive 1/2 hz vertical and 1/2 hz horizontal vibration isolation. More information at: http://www.minusk.com/ It is worth noting that the Minus-K platforms seem to offer the best performance/price ratio. Sub-herz performance at a fraction of the cost of its competition. Technology employed: Negative Stiffness animated gif Applications: Industrial.

Microscopy (scanning electron microscopes, etc.) Laser/Optical Systems Biology/Neuroscience Vacuum Isolation

We get to try out a Minus-K isolation platform here at The Analog Dept. Notes and observations: Link to notes page. Air Suspension; Active and Passive https://www.newport.com/ Above link to an online warehouse of industrial vibration isolation devices. A well-spring of ideas for both diy'ers and the pro. Vibraplane isolation platforms, active and passive. Vibraplanes: Sized from massive to light bench-top air suspended platforms designed to stabilize electron microscopes and other precision lab gear are recommended for turntable supports by certain members of the audio press. Kinetic systems produces these for several industrial purposes. Applications:

Atomic Force Microscopes Microhardness Testers Profilometers Balances Audio Equipment devices that require physical isolation from their surroundings, etc.

Vibraplanes are available as floor-standing work stations and as bench-top isolation shelves. The shelves are offered in "passive" or "active" models. The passive models must have their air pressure manually set and periodically maintained. (with a hand operated bicycle pump) The active models level themselves and are self maintained but require an air compressor as part of that system. Industrial models considered:

Models 2210 (passive), 2212 (active self leveling) offer vertical isolation as low as 1-1/2 hz. They operate in the vertical only. Model 2214 offers isolation in the horizontal as well as vertical. Isolation to 2.1hz vert / 1.8hz horizontal. Model ELpF active air isolation to vertical (1.75hz) horizontal (2.0hz) Note about the Kinetic systems active models; these do not sense acceleration. They only maintain level in an active mode

For use in audio systems see http://www.soundsofsilence.com/vibraplane-platform/ Their versions look less industrial and more appropriate within the context of the home audio system. specs. Silent Running Audio isoBASE web: http://www.silentrunningaudio.com Note: SRA offers several different versions of the isoBASE, each at different price points as well as performance capabilities. Webmaster's note: Based on various reviews I've read I can offer some description of the internal workings of these SRA isoBASE platforms. . For further reading I recommend the review links offered just below this text. Note the four spiked feet on the bottom. Each spike attaches to its own isolated internal module within the base. Each module within allows freedom of motion along six axes: fore, aft, left, right, up, down. The modules each contain 80 parts...so it says in one review. The modules are said to contain polymers. It seems mysterious to me. And isn't it noteworthy , there are no images anywhere of the insides of one of these bases. Must be top secret....;^) Hmmm. Or maybe, no joke, it really is. The company ceo Kevin Tellekamp, in more than a few reviews, claims to be using tech his other company uses on Nuke submarines and "this tech" is classified for national security reasons. So if it uses some of ....... Well, whatever, these products coming from SRA are not cheap. Links to reviews: https://www.ultraaudio.com/index.php/equipment-menu/51-silent-running-audio-vr-fp-isobase-equipment-platforms#most-read-equipment-reviews https://positive-feedback.com/reviews/hardware-reviews/silent-running-audio-virginia-class-reference-isobase/ https://www.tonepublications.com/review/silent-running-audio%e2%80%99s-ohio-class-xl%c2%b2-equipment-platforms/ Platforms/shelves designed to dissipate/drain vibrations coming from the component being supported. Neuance Platform shelves by Greater Ranges. No longer available. But an underground favorite isolation shelf that did not break the bank Black Diamond Racing Shelves: Carbon Fiber shelves Above photo: Chuck Miller's Teres. The custom TT base is cut from a BDR "The Shelf" and it stands over a Black Diamond Racing "The Shelf". Also employed in this setup are BDR cones and pads. The exact layer-by-layer build up for a "The Shelf" is considered by BDR to be proprietary and is not revealed. http://www.bdrsound.com Symposium Acoustics https://www.symposiumusa.com