Turntable Isolation or Coupling?

Discussion in 'Audio Hardware' started by MaJoon, Jul 10, 2018.

  1. MaJoon

    MaJoon Member Thread Starter

    Location:
    London
    Hey all,

    I'm looking to invest in some isolation for my turntable (and possibly other components soon after) and I've decided to go with the cheap & infamous IKEA APTITLIG bamboo butcher board to put under the TT. This will be sat on top of a standard furniture unit, which is made from sturdy oak. I need to decide on some isolation feet and I'm confused whether or not I need to isolate or couple the board from the unit, or the turntable to the board...

    I started looking at Vibrapods but have since read a lot of conflicting posts on other forums as to whether or not isolation or coupling would work best for this setup, and things started to go over my head! Any advice on this and recommendations for feet would be greatly appreciated. I'm in the UK and happy to fork out a fair bit for something that will make a huge difference, but I think things like the Stillpoints are a little out of my price range at the moment.

    I'm currently using a Project Debut Carbon but will be upgrading to a Rega Planar 6 in the near future, if that's any use.

    Cheers,
     
  2. KT88

    KT88 Forum Resident

    I'd go with something inbetween, say cork dots between the bamboo and oak. Sit the table directly on the bamboo. That should work well for the Rega.
    -Bill
     
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  3. chervokas

    chervokas Forum Resident

    A butcher block on top of a shelf is just like having one shelf on top of another, it provides no isolation. What you want out of your stand is rigidity. Bamboo IS a rigid material with good self-damping properties, but with a turntable the key is isolating the turntable from audio frequency structure borne vibrations and from subsonic low frequency vibrations -- like footfalls on a flexy floor -- that might excite the arm/cart's mass-spring resonance and/or cause the needle to jump out of the groove even. Your standard furniture unit of sturdy oak is probably not all that inert. I'd suggest using some kind of isolation between it and the butcher block. The trick if you're going to use elastomer isolation feet is to make sure you're picking the right feet for the weight of the butcher block and turntable you'll be putting on them. If you put too much weight on squishy elastomer feet, you just compress them and then they fail to isolate and just couple.

    Anyway, I'm going to presume that the oak furniture is neither all that inert nor all that light, so it flexes and holds on to the vibrations, so I'd try to isolate the butcher block from that before I put the turntable on the butcher block, and I'd use either some kind of compliant elastomer devices that convert movement to heat and that isolate in both the horizontal and vertical directions. Then I'd start with the table on the butcher block with whatever its standard feet are.

    You could try also decoupling the table from the butcher block too, but then you have to be little careful about any interactions between the two isolation schemes and their resonant frequencies and effective frequencies. I just just start decoupling the butcher block from the furniture.
     
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  4. jupiterboy

    jupiterboy Forum Residue

    Location:
    Buffalo, NY
    Maybe some Herbie's fat dots. I use those under the feet on my table and it is much better than the stock sorbothane. Get the weight of the table plus block and work from that.
     
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  5. timztunz

    timztunz Audioista

    Location:
    Texas and Brasil
    Sound advice. Simple and effective.
     
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  6. Waxxy

    Waxxy Forum Resident

    Location:
    Alberta
    I'm a fan of coupling but it really depends on your turntable, the rack, the floor and where you place the rack in the room. Heavier mass-loaded turntables are more immune to structure borne vibration than lighter ones and so will work better in 'coupling' situations. Lighter turntables may need isolation from the structure but are also more prone being excited by airborne energy, so they too may benefit from coupling to some type of mass. Experimentation is key.
     
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  7. ashulman

    ashulman Forum Resident

    Location:
    Utica, NY
    Try sorbathane under the block. Or bicycle tune method. Both cheap
     
  8. Jim Whithorne

    Jim Whithorne Member

    Location:
    Anaheim, CA
    33na3rd likes this.
  9. MaJoon

    MaJoon Member Thread Starter

    Location:
    London
    Thanks for the replies.

    I’ve sent the guys at Herbie’s an email to see what they think my best options are, but it looks like some kind of Sorbathane/fat dot could work well.

    Bill - when you say cork dots do you mean the simple ones you can pick up from most hardware shops or the ‘hifi kind’ that have black rubber on the top and bottom?

    I’m thinking of picking up some isolators for the rest of my system so it’d be ideal if I could do a bulk order at Herbie’s and get everything sorted in one go.
     
  10. criolf

    criolf Member

    Location:
    Singapore
    As you started with Ikea chopping board, I'll give you my experience, as I'm using their products at all levels for isolation:

    1. for speakers (Klipsch KG3.2, spiked feet):
    - they stay each on a "PROPPMÄTT chopping board";
    - under each chopping board, as suspension/isolation, I added 2 "PLASTIS Ice cube tray" (the ones shaped like flower/muffin, as they look to have more space to colapse) face down;

    2. for amp/pream/phono:
    - 2 GRUNDVATTNET Mat,
    - "KNAGGLIG Box" sides (did not assemble the box, just used the parts) on top of them

    3. for turntable (Michell Gyrodec), from shelf going up:
    - 4 (rubber?silicone? no idea) golf training balls,
    - on top of each an "Ikea 365+ coaster" face down (they are made of cork and "cup" shaped, so the balls don't roll out)
    - on them an "APTITLIG bamboo butcher board" facing up (normal way);
    - on top of it another "APTITLIG bamboo butcher board" facing down (so the sculpted channels match) with a rubber cord (basically a very long O-ring of 8mm diameter that I cut to fit) filling the channels, keeping the boards about 1-2mm apart;

    Works for me.
     
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  11. The FRiNgE

    The FRiNgE Forum Resident

    A question with two answers, stability and isolation; Stability isn't as much related to coupling, as the turntable must be situated on a stable surface. The ultimate would be massive block of granite, or marble. The turntable should be isolated from that. As @chervokas commented, the shelf or stand should be solid but self damping, but the key is that the turntable itself needs to have good coupling and isolation properties.

    A turntable not designed to isolate will not be good on isolation. This can not be improved by neither coupling nor decoupling. Turntable isolation for the most part relates to the turntable design, the damping properties of its plinth, and how well the arm couples to the record.

    So, coupling is more a function of the arm to the record, an unbroken, non-compliant closed loop. Isolation is of how well this closed loop, the arm to record, isolates from the outside world.

    Good examples of well coupled and well isolated turntables are the Linn LP12, Thorens, AR (the AR with a better arm like a Shure SME, Grado, Grace, etc) Other high end designs rely on massive plinths, but must also be self damping.

    My advice is to isolate. It is critical to place the turntable on a solid stand, The butcher block may help.. couple the block to the stand, isolate the turntable from the block. As I mentioned, coupling is more a function of turntable design, a closed loop of the arm (the stylus) to the record. The turntable plinth should be well damped, more massive ones are better.

    With a record playing between tracks, tap your finger on the top of the plinth. A dull thud through the speakers is acceptable. If you hear a "bong" or "ringing", or "booming", not good. No amount of isolation nor coupling will fix that. AR claims the plinth of an AR can be hit with a hammer, and the stylus will not jump. Likewise, tapping the plinth with a finger produces no sound through the speakers. I currently own an AR, have hit the top sharply with my knuckles. Both claims are 100% true.
     
    Last edited: Jul 11, 2018
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  12. willboy

    willboy Forum Resident

    Location:
    Wales, UK
    What he said.
     
  13. box of frogs

    box of frogs Forum Resident

    Location:
    Lincolnshire, UK
    You don't mention whether or not a wall shelf is out of the question, but IME, the most suitable isolation for a Rega turntable is this:

    Rega Turntable Wall Bracket in Black or White from Hifisound

    If the wall isn't solid, there are a number of solutions you can employ to ensure a good solid fixing. This would be where I would spend my money.

    If it has to be on solid furniture, then one solution might be to make something involving two layers of acrylic with another material between (constrained layer damping). The middle material in this sandwich should be less stiff than the acrylic, e.g. sheet rubber. Alternatively, you could try using a thin rubber layer between 2 layers of ply. This might reduce frequency but increase displacement. If you introduce a stiffer material in the constrained layer (e.g;. aluminium sheet), you can reverse this effect: it's either a low pass or high pass filter. Then you have the other issue of what footers to employ, e.g. ball & cup, sorbothane, etc. And finally, there are sprung versions, e.g. Funk Firm's Boing:

    Funk Firm Boing Isolation Feet

    As in all these things, experimentation is key: a suitable solution for one music room may not work in someone else's.
     
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  14. chervokas

    chervokas Forum Resident

    I don't see the point of coupling the butcher board to the furniture -- basically coupling one shelf to another then putting the turntable on the second self -- I'm not not sure what function the bamboo board is serving in that arrangement. Sure, maybe it's a more rigid and less resonant surface than the oak shelf below it, but it's coupled to the oak shelf so vibrations either is experiencing are passing back and forth between the two. Why not turn the rigid bamboo board into a rigid shelf that's decoupled from the furniture below it with a decoupling method that works at very low frequencies where footfalls and movement of a heavy piece of wood furniture are? Then you have a rigid, relatively inert surface, isolated from any problematic low structure borne vibrations from a heavy piece of wood furniture that may be on a flexy floor, to place the turntable on. If, while music is playing, there are vibrations present on the bamboo board after that, some kind of further decoupling between bamboo board and turntable might also be useful, as long as it doesn't have the same resonant frequency as the iso system below it. At least that's the way it seems to me. But there IS a correct answer, we just need one of our members with mechanical engineering background to come on this thread and tell us.
     
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  15. missan

    missan Forum Resident

    Location:
    Stockholm
    I don´t the is APTITLIG has any real benefit in this case, besides maybe looking neat. But if You should use it, it should be isolated from the furniture. In the real world proper isolation is hard to do, as we would like to have a resonance frequency that is lower than arm/cartridge resonance freq.; but it is of course doable.
    Personally I would just put the TT on the furniture and test how sensitive the TT is to this. Or even better use an IKEA LACK table.
     
  16. Vinylanswer.net

    Vinylanswer.net Active Member

    Location:
    New York,NY
    I have a rega rp6. For my isolation:
    Stock Rega feet replaced with Edensound Bearpaw Brass Footers.
    Table sits on a Mapleshade 2" thick Maple Platform. Maple rests on 4 sets of 2" Isoblocks.
    The improvement was not subtle!
     
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  17. G E

    G E Forum Resident

    Well Tempered turntables use squash balls for feet.

    I have a 3" maple shelf coupled with brass cones to my SolidSteel brand rack. My WT Amadeus sits atop. Concrete floor.

    Equipment stand is in a walk in closet and not between the speakers.
     
  18. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    another option would be to get a turntable with capable plinth damping and system isolation and rest directly on your stand, thus avoiding all the clap trap. They do exist and do work and look subjectively cleaner.
     
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  19. harby

    harby Forum Resident

    Location:
    Portland, OR, USA
    Isolation has a resonant frequency. If you hang your turntables by chains from the ceiling, like nightclubs used to do, it might be 1/2Hz. That way 100 people stomping on the ground don't cause records to skip. Can you jump up and down near your turntable with no ill effects?

    Just putting your turntable on a butcher block doesn't do much to "isolate". Only high frequencies that don't affect turntables adversely would be absorbed by the elasticity of the wood.

    Isolation works in conjunction with added mass. For example, a sheet of granite countertop might weigh 30 lbs in addition to the turntable. Then we add isolation below this, such as partially inflated kiddie bike inner tubes, and we can visually confirm that we have a resonance around 2Hz and higher frequencies can't pass through that buffer.
     
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  20. The FRiNgE

    The FRiNgE Forum Resident

    Good points, and I mostly agree. Actually I am not big on using the butcher block. I mentioned it only that the op may want to experiment with it. As I have pointed out, the turntable should be isolated.. nothing coupled to it (on this point we disagree somewhat) and that coupling mass to the plinth via spikes, or otherwise would be largely ineffective. Likewise coupling the butcher block to the furniture is ineffective.. except that the furniture be super resonant. Isolation can not be 100% in most cases, so we DO want to control resonances on the furniture.

    To add mass to the plinth, we need a more massive plinth.. not something it is coupled to. The turntable placed on a sturdy piece of furniture, simply, is enough. Should the floor be shaky, the furniture could be anchored to the back wall.
     
    Last edited: Jul 11, 2018
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  21. JBryan

    JBryan Forum Resident

    Location:
    Baltimore
    I don't know if its a 'Rule of Thumb' but I think isolation works best with suspended TTs while coupling is better for the non-suspended and TT's with more mass.
     
  22. The FRiNgE

    The FRiNgE Forum Resident

    Very interesting points, although respectfully I am not in complete agreement on some points. If one attempts to add mass to a plinth, this can not be accomplished by spiked feet, or even by bolting the turntable plinth to a massive block. To add mass, the block must become an integral part of the plinth. In order to accomplish this, the plinth (or base) needs to be intimately attached, such as a full glue surface, glued and clamped.

    An electric guitar would be a very good analogy about how mass coupling works. First of all, it's important for any guitar to be rigid, so that the fundamental resonant frequency vibrates through the guitar body and neck as one piece. If the body and neck are not intimately attached, such as high spots in the neck pocket... so that the neck makes only a few point contacts.. the guitar will not resonate as one piece. (and it will sound like cr^p) The neck couples to the body only by full contact, without voids. This is sound engineering for either a bolt on neck, or glued.

    Likewise, a butcher block attached to the turntable plinth should be intimate, without voids, essentially glued over its full contact area. Then and only then do we have mass added to the plinth, and its resonant frequency and self dampening changed ... hopefully for the better.
     
    Last edited: Jul 11, 2018
  23. swvahokie

    swvahokie Forum Resident

    You are correct, isolate the butcher block. I have one under my P6 and have tried both ways.
     
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  24. eflatminor

    eflatminor Forum Resident

    Location:
    California
    Wall shelf designed for turntables
     
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  25. swvahokie

    swvahokie Forum Resident

    Adding mass to the support is the very last thing a Rega needs. The new Rega wall shelf is extremely light but rigid. That is first choice. 2nd choice would be the Quadraspire Stage shelf, very light bamboo. Next would be the Ikea stuff, and I am not so sure it is not as good as the Stage, just not as neat.
     
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