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Discs of Silence isolation feet

Discussion in 'Audio Hardware' started by ggergm, May 25, 2015.

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  1. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    Look what I've added under my turntable:

    [​IMG]
    high res version

    These are the Discs of Silence (somehow I think there should be a dramatic musical cue whenever I type Discs of Silence). Made by Solid Tech from Sweden, they appealed to me because they used springs. There are a lot of isolation feet out there using everything from rubbery compounds through spikes and sharp points to ball bearings in cups. All of them have their proponents. Few external feet use springs. Yet the standard engineering solution for dampening vibrations in an automobile, railroad car, or even a tall building in earthquake zone involve using springs. Many turntable manufacturers use springs in their suspension but seldom have I seen them on external feet. Springs seem like the logical solution to vibration control to me.

    The standard Discs of Silence have three springs. Four of them sell for $350 and will support 100 pounds (45kg). $35 more will get you enough extra springs to go to six per foot which will then support 200 pounds (90kg). I'm using 4 springs per foot in my situation. I bought my Discs of Silence and extra springs through The Cable Company.

    For the skeptics out there, here are some tests Solid Tech did on the dampening capabilities of the Discs of Silence.

    The discs aren't small at 78.5mm (about 3") in diameter.

    [​IMG]
    high res version

    That's good because they had to support a 1" thick piece of stone from a local quarry in addition to my turntable.

    Biesanz Stone has been an active quarry in Winona, MN, for over a century. Many of the sidewalks in Winona are Biesanz stone, as are building exteriors. A Minnesota Dolomite limestone from the Ordovician Period, it is approximately 450 million years old and filled with fossils. I love the stuff and have it in and around my house. For $100 they made a 1" slab for me the dimensions of my turntable. They also filled in the pits in the stone with grout. Here is a raw piece I took off a junk pile at the quarry.

    [​IMG]

    Next is a picture of my set-up with the Discs of Silence and the Biesanz stone.

    [​IMG]
    high res version

    Let's go through the entire support, starting with the floor.
    • The oak floor is 85 years old and is over the old coal chute/oil tank room (you can see evidence of both). That means there are four solid walls under this corner of my house. The primary support for the turntable is good.
    • The rack is a B&O F1000 stand with the gray plank 1½" (38mm) of manufactured wood. One of the two main feet for the stand is in the foreground. Fiberglass, it is stronger than heck and right underneath the turntable.
    • 4 Discs of Silence
    • 30 lbs. of Biesanz stone
    • VPI Classic 2 turntable with the stock feet
    So how does it sound? Nothing short of phenomenal. Immediately I noticed my bass transients had dramatically improved. Drum hits are much faster and more impactful. In fact, I listened only to drum records the first night. I was also able to turn up my sub as the bass was so much cleaner. It got wooly before. Not now. I was hoping there might be a some improvement. I wasn't expecting this magnitude of change. My guess is most of this improvement comes from the Discs of Silence, not the stone, but I can't say for sure. It will be interesting sometime to replace the Biesanz stone with a piece of ¾" plywood. I'll report back when I do.

    When I crank it up and there is a lot of bass, if I put my fingers on the B&O stand, I can feel the bass. I can't feel anything on either the stone or the turntable's plinth. That's a good sign.

    The only disadvantage is this set-up is top heavy. Give it a good shove and it will rock. Well damped, the swaying will stop completely after 3-5 seconds but you don't want to do knee drops in front of the turntable. The record will skip.

    I'm very impressed with the Discs of Silence. Along with the Biesanz stone, I got more than a $500 improvement in my sound.

    [​IMG]
    high res version
     
    Last edited: May 25, 2015
    33na3rd, 4xoddic, Jtycho and 5 others like this.
  2. The Pinhead

    The Pinhead SUDACA ROÑOSO

    Wow; I got the very same results with a wall-mounted shelf:D. No offense implied;)
     
    ggergm likes this.
  3. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    Yeah, but does your shelf have fossils one tenth the age of the Earth? :D No offense taken. ;)
     
  4. Gumboo

    Gumboo Forum Resident

    Location:
    New Orleans area
  5. missan

    missan Forum Resident

    Location:
    Stockholm
    Looks like a very sound solution that really should work well. Don´t know if I would choose PVC though.
     
  6. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    Agreed the DIY version is impressive for what they are trying to do. I don't know if I'd trust four of the them to hold 100 pounds, even with additional springs, which is about what the Discs of Silence have to support in my set-up. If the PVC cracked, everything would go tumbling down.

    The discs themselves are superbly finished aluminum. I goofed around with them a lot while taking the pictures of the three, four and six springs versions, plus then assembling my final set of four spring pucks. There was never a hint of the discs getting scratched by the ends of the springs. Fit and finish were immaculate.
     
    Last edited: May 25, 2015
  7. Gumboo

    Gumboo Forum Resident

    Location:
    New Orleans area
    I agree! I don't think the DIY version would be trustworthy under heavy loads.
     
    ggergm likes this.
  8. missan

    missan Forum Resident

    Location:
    Stockholm

    Yes everything looks very good. In principle one is getting an suspended design but with more stability. An earlier version had rubberbands that also worked very well, but springs are a better solution. For those with a Rega, Project or similar designs these discs directly under the TT should be an enormous improvement IMO, a sound solution using mechanics.

    Have You looked at resonance freq which should be about 4Hz for best isolation of higher freq, just as with a suspended design?
     
    ggergm likes this.
  9. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    Not to mention Swedish but then I'm sure you didn't notice that. ;)
    I don't know how I would calculate or measure this. Any advice?
     
    Last edited: May 26, 2015
  10. Thanks for an outstanding and detailed review of your experience with these Discs of Silence. Much appreciated!

    In the past I've always used a combo of butcher block and hockey pucks, that were covered with 3" furniture felt pads on both sides. I've been very pleased with the results and still might stick with this approach. However, I'm becoming more interested in seeking out other alternatives now that I've upped my vinyl front-end. Isolation and vibration control is high on that list of alternatives.

    I have some other things on my list of priorities (some not audio related), but I'm definitely keeping rhe Discs of Silence in mind. Thanks again!:)
     
    Sailfree, Music1212 and ggergm like this.
  11. missan

    missan Forum Resident

    Location:
    Stockholm
    What! Swedish! No I didn´t see that. :)

    Do You get a bounce if You get the TT a gentle push from above at about the centre of the TT? If so the time between each peak could be about 0.5-0.25s for 2-4Hz in res.
     
    ggergm likes this.
  12. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    Yes, I get a bounce which sustains for a few seconds. I have a friend coming over today and we'll try timing the resonance as I count out bounces but I think the best bet is to film it. It should be then relatively easy to time the bounces within an editor.

    I'll let you know the result of today's experiment. Thanks for the suggestion. I love kitchen science like this. :righton:
     
  13. missan

    missan Forum Resident

    Location:
    Stockholm

    It´s fun. The reason to have bounces at low freq is that everything above the discs is isolated from freq higher than this res freq, and moves simultanously with the very, very low freq. Especially when using undamped springs. It´s solid mechanics and can´t be compared with many other solutions.
     
    ggergm likes this.
  14. I'd think you'd get ringing in the springs. Springs are fantastic at picking up and transmitting sound (see spring reverb here: ).

    I'd expect to see a rubber/plastic sleeve on them to dampen them?
     
    Last edited: May 26, 2015
    ggergm and Vinyl Addict like this.
  15. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    Yes, you get ringing because this is the resonant frequency of the reverb. You want ringing. That's how the reverb works. You might was well acknowledge the resonant frequency of a guitar string. It's the note being played.

    What missan brought up is you accept that you will have a resonant frequency of the turntable system. It's inevitable. You make the resonate frequency so low it doesn't matter. It's well below any sounds the stereo can play. The turntable might get excited by passing trains - I have those and they shake the whole house, including the turntable - but not by the music. Plus by the time we move up in frequency toward the musical range, the springs won't resonant. They can't store nearly as much energy at higher frequencies. They can't ring. Instead of dampening the springs with sleeves, design the feet so that the springs won't vibrate at those higher frequencies.

    I timed out my turntable bounces with my buddy. We did five runs of my counting to ten in the middle of the bouncing. He timed it. We averaged them out, finding one turntable bounce took .23 seconds. The resonant frequency would be about 4Hz. Tomorrow we are going to try filming it but for a first approximation, 4Hz is good.
     
    Last edited: May 26, 2015
  16. missan

    missan Forum Resident

    Location:
    Stockholm
    Very nice! Some say damp the springs, some say don´t. I would go with the latter, if there aren´t any problems. That means we are not adding a force to damp the amplitudes, which is done if we damp, this force will also act on the TT. (in principle)
     
    ggergm likes this.
  17. FJC1966

    FJC1966 Forum Resident

    Location:
    Lancashire, U.K.
    Didn't know that you could 'burn' someone with a 'cool' response....what a Forum!
     
  18. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    That 4Hz resonance? Watch out. It's a heck of a ride.

    When I bounce my turntable, I press down hard so that the Discs of Silence bottom out. Then I let go. It's quite a jolt but how it keeps going is what's impressive. I timed it out tonight. It took 17 seconds until I was pretty sure the VPI had stopped vibrating.

    Now that's a resonance!

    Why am I strangely proud of that fact?
     
  19. missan

    missan Forum Resident

    Location:
    Stockholm

    Either because isolation at higher freq is a piece of cake (lätt som en plätt) or that 17 is a prime number.
     
    Last edited: May 27, 2015
  20. Bad Samaritan

    Bad Samaritan Forum Resident

    Location:
    Phoenix, AZ
    Can you tell me what the diameter and height is of the outer ring, and also the material? I have a set of the feet of silence inbound to me but thinking about making a DIY version of these to try also. (A more robust DIY version, not the one linked above)
     
  21. erniebert

    erniebert Shoe-string audiophile

    Location:
    Toronto area
    $350 for four plastic rings and a few little springs? :sigh:
     
  22. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    I look at it as $350 for the perfect isolation of my turntable. The solution often looks overpriced when all you see the final result. It's the engineering along the way that's expensive.

    If you don't want to spend $350, there is a very nice DIY version upthread that would be a fraction of that amount.

    I easily got a $350 improvement in sound. That's what I paid for.
     
    missan and 1970 like this.
  23. erniebert

    erniebert Shoe-string audiophile

    Location:
    Toronto area
    I'm happy for you, but none of my components cost me $350. The DIY solution looks nice. Maybe I should make a bunch and sell them. :)
     
    ggergm likes this.
  24. ggergm

    ggergm Sir Guy Thread Starter

    Location:
    Minnesota
    I'd agree. Maybe you should! :)

    A less expensive competitor might drive the price down. It's happened before.
     
  25. Scott Wheeler

    Scott Wheeler Forum Resident

    Location:
    ---------------
    Nice explanation on the basics of suspensions. There are two main factors with suspensions. The resonant frequency and the self damping factor. They both affect the attenuation of all vibrational energy above the resonant frequency. All vibrational energy bellow that frequency can pass freely through the suspension. 4Hz is good. My Aurios 1.0 come in at about 1.5 Hz. Love em.
     
    ggergm likes this.
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