sub spikes?

Discussion in 'Speakers' started by Kevinkall, Jul 14, 2003.

  1. Kevinkall

    Kevinkall Second Unit

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    I have the Sony WM40 and my apartment is carpeted. Should I add spikes to the bottom of the sub? Will this enhance the bass? Also where is a good place to get spikes? I have did the Polly-fill mod and was wondering if there is anything else that I can do to enhance my sub? I want to get the best possible sound from my sub. Thanks in advance.
     
  2. Lee Carbray

    Lee Carbray Second Unit

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    Spikes will help your sub get a good sturdy coupling to the floor. Whether you will be able to tell the difference in sound only you will be able to tell. As for where to buy them, Parts Express is as good a place as any I suppose.
     
  3. Kevinkall

    Kevinkall Second Unit

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    Thanks...are there any other tweaks that I can do on my sub?
     
  4. Terence B

    Terence B Auditioning

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    You might try the MODPODGE treatment, doesn't fo much for the boominess but does seem to tighten up the bass a bit....

    I bought this same model as an inexpensive sub.

    For 125 bucks I was not expecting nor did I get SVS or HSU performance.

    At very loud levels I did find the audio performance very boomy and with no definition, this varied with xover and volume settings.

    I went to Walmart and bought a pound of Poly-Fill, and a bottle of Mod Podge.

    First I sprayed the interior with adhesive and carefully stuffed the cabinet with somewhere between 1/2 to 3/4 of a pound of polyfill, leaving the tuning port open.
    I then applied 3 thin coats of Mod Podge to the front of the speaker cone (not the the surround or the dust cap) and also two coats to the rear of the cone.

    After reassembly I gave it another audio test.

    To my ears the difference was quite a change, no it still didn't sound like an SVS or HSU but now the boomines was greatly reduced and the tightness and bass audio definition was improved.

    I also bought the spikes from Parts Express , however I haven't installed them yet - I would expect a very small but noticeable improvement.

    FWIW
     
  5. Kevinkall

    Kevinkall Second Unit

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    Thanks Terence for the info!

     
  6. Terence B

    Terence B Auditioning

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    Kevin -

    No you don't have to spray the adhesive, I just did it because I had some spray adhesive at the house and I figured it would remove any possiblity of the poly-fil loosening up and falling into the back of the speaker.
    BTW, make sure you keep the internal tuning port opening clear of the poly-fill. It is a bass reflex design and the reflected sound waves have to exit the enclosure, if you plug it up you'll loose efficiency(audio volume) and have to crank it up to compensate.

    As you know, the driver in that sub uses a rather inexpensive paper cone.
    The MODPODGE (it's an art decoupage sp? liquid coating) treatment will seal and stiffen up the cone a bit, that will improve the bass tightness a bit. The next best thing would be to replace the driver with one of higher quality, but your going to drop another 100 bucks to do that....

    As far as the spikes go, if you have a carpeted wood floor I'd definitely recommend the spikes. If you have carpet over a cement slab it's probably a coin toss, the spikes will keep the enclosure from the small slide vibrations on the carpet and would probably help a small amount.

    For the price I payed the sub has worked fine for me for the last half a year, but I did just buy a SVS PB1-ISD to upgrade my system.

    Best of luck -
     
  7. Kevinkall

    Kevinkall Second Unit

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    Thanks for the advice!
     
  8. Brett DiMichele

    Brett DiMichele Producer

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    Kevin,

    I can think of two more upgrades I would do to the SAWM-40
    if I had one..

    I would take the driver back out and I would cover the
    interior walls with either heavy undercoating or dynamat
    and I would also construct braces to tie the top to the
    bottom and the sides to eachother. The PolyFill makes the
    enclosure seem "larger" by slowing the airspeed. This gives
    the sub a lower tuning. But the polyfill does nothing to
    dampen the cabinet and in the case of the WM-40 it could
    use some dampening.

    The problem is that Sony uses Chipboard in the construction
    rather than MDF from the pictures I have seen. Chipboard is
    not as strong or as dense as MDF and thus would have a
    higher resonant frequency. I belive by bracing and dampening
    the enclosure you could clean the bass output up substantialy.

    www.partsexpress.com sells numerous types of good dampening
    material from cheap to expensive.. The Asphalt or Vinyl mats
    would probably add adequate dampening control to the walls.

    Here is a picture of the inside of my DIY sub, you could
    make braces like this, easily by measuring the inside wall
    dimensions, cutting the braces then glueing them in with
    some good wood glue.

    [​IMG]
     
  9. Kevinkall

    Kevinkall Second Unit

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    Thanks Brett for the info!!! Good stuff!!!

    I'm going to put some spikes on it and I'm also going to pick up some CASCADE VB-1S PRO QUIET KOTE DAMPING SPRAY. I'm not sure how to add braces to the inside of the cabinet without taking the whole sub apart. I'll try the spikes and the daming spray and see what I think.
     
  10. Terence B

    Terence B Auditioning

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    Brett-
    Good Idea on the bracing (slaps forehead saying "why didn't I think of that!").

    Kevin if you are buying these spikes from Parts Express, I'll tell you what I just did.

    Last nite I decided to install them, even though I just ordered a new sub.
    I found that the internal location of the ON/OFF switch housing really screwed up any practical way to drill the mounting holes in a symetrical pattern.
    The diameter of those spikes perfectly matches those little round rubber vib isolators on the bottom of the sub, I just used some silicon glue to bond the spikes right to those rubbers pads. Quick and easy - no dissasembly or drilling required.
     
  11. Kevinkall

    Kevinkall Second Unit

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    WOW! Thanks for the tip! I likes no drilling!
     
  12. Brett DiMichele

    Brett DiMichele Producer

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    Kevin,

    Adding braces really isn't hard at all. You just measure
    the inside dimensions wall to wall and then cut the brace
    to that size. Slide it in the hole and then fanagle it into
    place. Just make sure it's not so tight that you have to
    beat it into place. It should be snug but not to the point
    where it will bow the walls of the sub.

    But yes I would try the cascade first and see what that
    does. It should help a great deal. The SAWM-40 is a great
    sub and with a few lowbuck mods can sound even better.
     
  13. Kevinkall

    Kevinkall Second Unit

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    Thanks Brett, I'm going to give it a try this weekend.

    Does it matter what kind of wood you use to brace, and just use wood glue to keep them in place?

    Thanks again for the helpful tips. Since I can't really afford to upgrade I want to get the best possible sound from what I have.
     
  14. Brett DiMichele

    Brett DiMichele Producer

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    Kevin,

    I used MDF because it's what I made the box out of and it
    wasn't a problem for me to cut it to any dimensions I needed.


    It would be kind of pointless to buy a 4'x8' sheet of MDF
    just to cut out a couple of braces so yeah I say you can
    use something else. You could use 2x4 material or any other
    wood.. After it's cut to size test fit the part. You want
    it snug but not so snug that you can't get it into place.

    Then apply some carpenters glue and let it cure.. after the
    bracing is done then go ahead and spray the dampening spray
    on everything..

    One note of caution here... If Sony's amp is exposed inside
    the enclosure do NOT spray it with the dampening stuff..
    You don't want that on the amp so if the amp is exposed you
    may do well to remove the amp if you can (probably not) or
    just mask it off really good!

    And also spray that stuff outside... You don't want to be
    breathing the fumes inside (plus you don't want to get over
    spray on anything)..
     

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