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What's under your turntable?

 

-edible zone-

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 Dictionary 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:
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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:
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

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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_____________________________________________________________horizontal rule

Mapleshade ISO Blocks

https://mapleshadestore.com

Maryland, USA

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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 thumbnail for full size image)

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 standard within nightclubs."



Link to the company website: https://www.isonoe.com

 

Isonoe M6. and  Universal dimension sheets above.



Pneumatic Syspension (air)

Pneuance Audio https://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 thumbnail for full size image).

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Magnetic Levitation Feet:

  -Opposing magnets repel-

   (hint: click thumbnail for full size image)

Clearaudio Magix²: Magnetic levitation isolation feet. No Longer Available except as....used sets at Ebay, Audiogon, Canuck AudioMart and US AudioMart, etc

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  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:

  

above: Black Diamond Racing cones and pucks.

https://www.bdrsound.com

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  Cone Feet in Ceramic

DH Labs Golden Sound -- DH Cones

   (hint: click thumbnail for full size image)

above: photos from the site owner'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

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Mapleshade Brass Footers for speakers and electronics

https://mapleshadestore.com

based in Maryland, USA

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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 that dates back to the 1980's.

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VIBRAPOD Isolators and Cones

   

Web: http://www.vibrapod.com

St. Louis, MO, USA

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Stillpoints:

Cone Feet with internal array of ceramic bearing balls designed to dissipate vibrations coming from above and below.

 

https://www.stillpoints.us

Wisconsin, USA

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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

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 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 thumbnail for full size image)

 

 
http://www.townshendaudio.com

UK based

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 ---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

  (hint: click thumbnail for full size image)

 

EMT 930-seismic.jpg (45557 bytes) product number: 9 930 900 First versions were designed and built by Studer.

From the book; "Deutsche Perfektion: The History of the Legendary EMT Turntables" by Stefano Pasini, we find some useful information on these isolation devices. To summarize the narration, I can say that Stefano tells us that the 'Shock-Absorber Frames' were originally designed for studio use, by Studer, where the EMT turntable would be fitted to a console on wheels and moved about into less-than-ideal venues where floor vibrations and also ambient (airborne) vibrations could interfere with the performance of the deck. Originally designed for the EMT 930, another larger version was made available for the EMT 927 deck. Year of introduction: 1976. Stefano tells us that this 'seismic base' became very popular among EMT users. In response to great demand, there was a simplified reproduction of this base that was made available. The earlier version was regarded - allegedly - as better.

  

Available for sale here: https://www.g-t-i.de/page.php?lang=en&page=frame

based at Lahr, Germany

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Gingko Designs: A platform/base that provides Isolation by means of springy Squash Balls between upper and lower plates.

Applications: Hi-Fi



https://www.ginkgoaudio.com/
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Piezo-Electric Active Isolation bases, shelves and platforms

Halcyonics Active Vibration Isolation

 

Some of the applications:

headquarters: Goettingen, Germany

web: https://accurion.parksystems.com/active-vibration-isolation/products

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Piezo-Electric Active Isolation Bases, shelves and platforms.

Herzan TS series : web: https://www.herzan.com

 

(no air) sub herz active vibration isolation across 6 degrees of freedom

Piezo-Electric

Applications:

Headquarters: Switzerland

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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

  

   Minus-K animated gif

Applications: Industrial.

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A custom order Minus-K for ken Fritz's very special, "no holds barred" turntable".

  Link to page

An Interview with Ken Fritz on Eliminating

Vibration in High-End Audio Playback

Audiophile, Ken Fritz, talks about the critical nature of eliminating vibration in audio playback, and how technology solutions like Negative-Stiffness vibration isolation have enabled the exceptional performance of his latest, quite unique and much applauded, high-end home audio system.

by Jim McMahon

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Minus k hands-on report. (link)

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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:

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:

For use in audio systems see https://www.soundsofsilence.com/vibraplane-platform/ Their versions look less industrial and more appropriate within the context of the home audio system.

 

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Silent Running Audio isoBASE

web: https://www.silentrunningaudio.com

  

   (hint: click thumbnail for full size image)

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 are out of date) ed note!

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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

  #  

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Black Diamond Racing Shelves: Carbon Fiber shelves

  (hint: click thumbnail for full size image)

Above photo: Chuck Miller's Teres. The custom TT plinth 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

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Symposium Acoustics

https://www.symposiumusa.com

shelves: different densities of structural foam adhered between upper and lower aluminum plates.

  (hint: click thumbnail for full size image)
 

The denser foam is at the outer layers. The softer less dense foam is sandwiched in the middle.

Racks:
 
Wall Mounted Racks
The most common benefit received when using a wall-mounted platform to support a turntable is relative isolation from floor vibrations..... such as footfall. However, if the building construction is light and flexible, there still can be some disturbances that reach the turntable by traveling through the building structure itself. Caution must be taken to avoid placing your TT support in room corners. Lower frequency airborne acoustic waves tend to collect in room corners and then bombard the tonearm cartridge working there.

  Apollo Wall Rack (commercial) light rigid

  Target Wall Rack (commercial) light rigid

  Phonosophie (commercial) light rigid

  Mana Wall Rack (commercial) light rigid
 (hint: click thumbnail for full size image)

 

Racks:

Floor Standing Racks with seismic isolation capabilities

(click on thumbnail image to view full size image or link to a page that does)

  The stand beneath the Rockport Technologies System III Sirius Turntable. Floor standing, air suspension actively leveled. Integrated into the turntable support stand. discontinued.

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Townshend Engineering Hi-Fi

 


Seismic-Isolation-Stand-Townshend-Hi-Fi-rack.jpg (23622 bytes) Townshend-hifi-rack-Seimic-Isolation-Stand-980x360.jpg (49893 bytes) Isolation from the floor via coil springs.

https://www.townshendaudio.com
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Arcici SR1 Reference Suspense Rack. The component shelves hang from an air-bladder suspension located at the top of the structure. The system is passive. Air pressure is maintained using a bicycle pump to keep the bladder inflated.

  (hint: click thumbnail for full size image)

Arcici Lead Baloon (vintage and out of production)

 

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Floor Standing Racks

Silent Running Craz Reference isoRack plus    

web: https://www.silentrunningaudio.com

 
 

There is more to these racks than what you see.

Silent Running employs a frame within a frame design in these products.

The inner frame material is titanium.

Unfortunately, there are no photos or cut-away-illustrations to describe how this design is implemented --- none that I've seen anyway.

Below are some links to product reviews.

http://www.theaudiobeat.com/equipment/silent_running_audio_scuttle.htm

http://www.soundstagenetwork.com/revequip/silentrunning_craz_4.htm



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Mana Acoustic

  A light rigid floor support in steel and glass from Mana (discontinued)
(editor's note: it does not look rigid)

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The Teres Gibraltar Stand.

  Rigid, internally damped, high mass.

Atop the Gibraltar stand is the perfect compliment; the Teres Certus 460 direct drive turntable.

http://www.teresaudio.com

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Billy Baggs Pro Stand

  High Mass and Rigid. A Billy Baggs Pro stand supports a massive 3 inch thick granite plate which in turn supports a massive non-suspended turntable, a Redpoint Testa Rossa XS. Note how the Redpoint doesn't use footers of any kind, rather its base and motor pod sit flatly over the granite. Thanks to Wes Bender for sending in this photo. The rest of Wes's system pics can be viewed here.

As of this date I can't find a web address for Billy Baggs audio furniture products.

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  Tabula Rasa. In Maple. Photo courtesy of Werner Ogiers.


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Acoustic Solid

https://www.acoustic-solid.com

In the past their larger turntables came with dedicated turntable stands. Like the one below

     Thorston Loesche's massive Acoustic Solid stand supports a non-suspended Acoustic Solid "Solid One" turntable.. Rigid, high mass. And a dedicated turntable stand.

Link to Thorston's page here at The Analog Dept. https://www.theanalogdept.com/thorsten_loesch.htm

Based in Germany

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Townshend

 

Vintage passive pneumatic:

Townshend Seismic Sink (discontinued) passive pneumatic (air bladder) platform Applications: Hi-Fi. Comes with bicycle pump to inflate the inner-tubes within.
 
  (hint: click thumbnail for full size image)

Vintage affordable pneumatic isolation. No longer offered....and easy to duplicate in a diy project.

http://www.townshendaudio.com

UK based

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Do It Yourself Racks, Stands and Wall-mounts


  steel tube weld-up diy wall rack.


  (hint: click thumbnail for full size image)
Above: wall shelf designed and built by Bushman. This design allows for suspension tuning of the turntable from underneath.

  diy floor standing base / neuance shelf / teres







Audible Effects of Mechanical Resonances in Turntables (pdf) (click to open into your Adobe Acrobat Reader)