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Do spikes on a sub make much difference

Discussion in 'Subwoofers' started by Jon Weaver, Feb 13, 2002.

  1. Jon Weaver

    Jon Weaver
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    My sub slight rocks on the spikes. One spike it about 1mm too short so it wobbles every so slightly.. When I get some really deep base, the box vibrates like mad and makes a noise like the driver is blown.

    But its just the effect of it wobbling on the spikes and the 4th spike hitting the floor..

    No matter how many times I try and adjust it, I can never get it to sit on all 4 spikes at the same time. As I have a concrete floor under the carpet, it just wont sit level.

    I am tempted to take them off, but worry what effect this will have on the sound.

    Does anyone have any thoughts?
     
  2. Jase

    Jase
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    How about putting a thick piece of carpet under the sub?

    One of the spikes on my Rel is bit shorter than the others, but the carpet is quite thick with a type of lino underneath so it doesnt wobble at all.

    Either that or buy some more spikes of the same length.
     
  3. Jon Weaver

    Jon Weaver
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    I probably didn't make myself clear.. The spikes are adjustable and are already on carpet.

    The problem is that the weight of the sub pushes the spike through the carpet where it makes contact with the concrete underneath.

    It it wobble, I adjust the spike so that it doesn't.. This works OK for big movements.. But when it comes down the last mm or so, I just can't get it right..

    I guess that this is because the concrete is not totally flat.. I have it in a spot and need to make spike 3 longer... I remove the sub, adjust the spike and put it back in the 'same' place.. But now it rocks the other way.

    If the floor was wood (under the carpet), it wouldn't be a problem as the spikes would just dig in.. But on concrete, it just doens't work.

    It would just be easier, not to have the spikes.
     
  4. Stuart Wright

    Stuart Wright
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    Interesting. I wonder if it would be worth taking SPL readings of the sub with and without spikes and seeing if there is a difference.
    To anyone who says they can't get the spikes level, I would just say keep trying.
    My sub does not have the spikes attached, but then I have a real fear that if the sub had spikes it would destroy the concrete floor. (I saw it being layed - I can imagine it crumbling under very low vibrations).
    Anyhow, I'm happy with the sound from my sub without spikes.
    Then again I'd probably get a hernia trying to lift the sub up to fit spikes anyway!
     
  5. Jon Weaver

    Jon Weaver
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    The other problem with concert is the fact it can chip.

    Say you put it down and its level, 3 of the spikes might be on the cement part (which could crumble), but one of the spikes might be on a granite chipping. which wouldn't crumble.. Result would be a slight wobble.

    This is what I think I am getting. I get it level, but a few days later it starts to rock again.

    And you wouldn't belive the noise it makes when its a fraction out.. As one if the spikes is just touching the floor, it vibrates and sound exactly like the driver has blown.

    I might have to take them out and see what happens.
     
  6. David Bier

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    Why not put your sub on Vibrapods?
     
  7. Jon Weaver

    Jon Weaver
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    Ehh? Vibrapods?? I think that my missus has one of those in her top drawer :)

    Never heard of them.. Please tell me more!
     
  8. Ian J

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  9. David Bier

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    Alternatively, go to the UK distributor, http://www.stoneaudio.co.uk/, and get them for £20 a set. Voila, well isolated sub and no more chipping concrete problem!
     
  10. magking

    magking
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    Or take a look at theese superspikes www.soundcare.no I use these under my sub and front speakers. They doesn't seem to have a distributer in the UK, but they have a web shop.
    (By the way, to get the price in £, divide by 13)
     
  11. Monster

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    I was told once that you can put a 2 pence under each spike to stop this sort of thing.

    Don't know whether it works, I've never tried it. It may stop the rocking/vibration but I thought the Sub cabinet should move as little as possible. Anything that sits on a carpet that you then put the sub on will have a bit of spring to it.

    Might be worth a try.
     
  12. GaryG

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    Jon

    Newtons third law of motion comes into play here.

    "For every action, there is an equal and opposite reaction."

    If your sub has a vertically mounted driver then the spikes will indeed be making a difference, they will add punch and dynamics to the bass because they will stop the sub moving as the cone is being pushed out.

    If your sub has a horizontally mounted driver then the spikes will have less impact depending on the weight of the sub as the cone movement will be causing a hopping action.

    Can't tell from your description of the problem whether the concrete floor is very uneven or not. Are you adjusting the spikes with the sub place? Start by having all the spikes screwed fully into the sub and then only screw out the spike where the sub rocks, don't move the sub to do the adjustment. You will eventually get it to work unless the floor is very uneven in which case you might want to put a paving slab (don't laugh) under the sub, you will probably need to cover it with a piece of carpet or a rug to keep the wife happy but it's worth the effort. I use Mana Acoustic stands for my kit, a total of 60 spikes to adjust, not fun I can tell you.
     
  13. steev

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    Just a though based on something I read. How about getting rid of one spike and moving an adjacent one to the middle of a side. With 3 spikes they should always all be in contact with the floor.

    I read about this in the interesting guide I downloaded from www.russandrews.com. Worth a look.

    Steve
     
  14. smarty

    smarty
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    I have a wooden floor so to avoid having the spikes digging in to the wood and ruining the floor I followed some advice that I found on a hi-fi forum. I have glued some felt around 1 pence pieces (used 2 pence pieces under front speakers as they are bigger) and put the spikes on these. Result is rock solid sub (after adjusting spikes), nice tight bass and no damage to the floor.
    Try using this method with your sub on the carpet. Try and get the coins to settle into the carpet between the piles so that they're not sitting on top of it so much. With the weight of the sub they should settle down nicely once the carpet squashes a bit. You've got nothing to lose (apart from 4p and some felt!).
     

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