1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  

Let's say you want to floor isolate this:

Discussion in 'Amps and Cabs [BG]' started by amos, Feb 25, 2008.


  1. amos

    amos

    Oct 23, 2003
    SE Portland Oregon
    2290915230_ccfe963c38.


    GREAT GRAMMA is $100. Is there a cheaper alternative?
     
  2. jkdahlman

    jkdahlman Ambitious But Rubbish

    Jul 13, 2004
    Baltimore, MD
    Cool rig. Might as well spring for the great Gramma or even 2 regular Grammas. I use one under my stuff all the time & wouldn't be without it.
    I looked for a long time for a cheaper way but, in the end, decided my time was worth more than it would cost me to make a not-as-good version of the Gramma. Besides, after spending all the money we do on all that gear, what's another $100 if it's the best solution? YMMV, IMHO, etc. Good luck on the search.
     
  3. pacAir

    pacAir

    Feb 25, 2008
    N/W Oregon
    I agree, just suck it up and buy the Gramma pad that works for you. These things flat WORK and I carry 2 of the regular models depending on the gig or stage: one to isolate my rack (head) from the stacked cabinets and one to isolate the stack from the stage!

    SK_Bass_1c.

    This allows not only cleaner bass (minimized sympathetic stage resonances) but also keeps the bass frequencies from constantly rattling the electronics in the rack, thus increasing their life expectancy dramatically!

    I used to think the same thing as you... can't this be done cheaper? Perhaps it can, but Auralex really did their homework on the Gramma pads (more like a platform... in the photo it is under my rack head) and I was so impressed with my first one I bought another one and have NEVER regretted it!

    Great stuff!

    :bassist:
     
  4. amos

    amos

    Oct 23, 2003
    SE Portland Oregon
    I do understand the GRAMMA pad works, as I owned one a few years ago. Unfortunately it was stolen from me, along with a tape recorder, practice amp, and few other odds and ends. I just figured if I could two pieces of platfoam and a piece of studio foam, I could build the MDF board for less money. Unfortunately they only sell platfoam and studio foam in kits. So Great GRAMMA it will be, probably followed by a regular GRAMMA to go between the top cab and amp. I am currently unemployed at the moment, is the reason I am asking.

    BTW, nice rig, and cool pickguard for the P.

    Looks like the A/B/Y box will have to wait, as an Iso pad is more important at this point, after two terrible experiences with big ass hollow stages.
     
  5. +1 for either the gramma pad or the great gramma

    ive got 2 grammas and i dont gig without them
     
  6. Crockettnj

    Crockettnj

    Sep 2, 2005
    North NJ
    what exactly does the gramma pad do? is it to prevent vibrations? it isnt physically moving the cab far enough away form the floor to "uncouple" it. Or is it?
     
  7. amos

    amos

    Oct 23, 2003
    SE Portland Oregon
    http://www.talkbass.com/forum/showthread.php?t=384895&highlight=two+forces+boundary

    The short answer is decoupling separates the cab from the floor, which is a good thing if its a hollow (boomy) stage and doesn't matter if it's not. With the GRAMMA pad underneath your amp, you are hearing purely the speakers, instead of the speakers and some of the stage/floor resonating.
     
  8. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Gives some mechanical uncoupling but of course retains acoustic coupling/boundary effect.
     
  9. amos

    amos

    Oct 23, 2003
    SE Portland Oregon
    I would like to note, that boundary reinforcement is a good thing usually, IME.
     
  10. TomB

    TomB Supporting Member

    Aug 24, 2007
    Vermont
    +1 for the Gramma, though I find casters can do about the same thing for a 4X10 on a wooden stage. Some coupling is not always a bad thing.
     
  11. amos

    amos

    Oct 23, 2003
    SE Portland Oregon
    Coupling is one of two things;

    A) bad (hollow stages)
    B) no effect.

    I cannot think of an instance in which coupling could be "good". Boundary reinforcement however can be a good thing.
     
  12. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    In the optics lab, I get excellent decoupling with a piece of plywood on top of a bike innertube. It's good enough to do interferometry in a room with a vibrating floor. One can get tubes of varying diameters at WalMart, made for kids bikes.
     
  13. Mcrelly

    Mcrelly

    Jun 16, 2003
    Minnesota, USA
    ON THE CHEAP you might look for some stiff packing foam, STIFF. If you know any I.T. professionals or maybe someone who works with foam (not the old mushy stuff) packing materials.

    I worked for a company that bought a lot of DELL computers and had some pretty nice "closed cell" foam. ya know the stuff thats hard to squeeze and almost impossible to tear or cut???

    search online foam dealers or packing materials. also check out sleeping pads or flotation toys.

    remember flotation "noodles" they are like 6' long, 4" dia. and a hole down the center?? I split the noodle down the middle and cut them into shorter segments. I used a couple at a time. when they were squished flat (I hardly moved my gear) I'd swap out the foam for some uncompressed ones.

    good luck!!
     
  14. Mcrelly

    Mcrelly

    Jun 16, 2003
    Minnesota, USA
    how would you arrange them so his gear doesn't tip over??
     
  15. pacAir

    pacAir

    Feb 25, 2008
    N/W Oregon
    ...a couple of kids on their bikes?

    :D
     
  16. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    What I do with optics gear is simply to center the gear on the platform. This is less likely to be satisfactory with a bass amp, of course. As soon as the Mosh Girl slams her head into the side of your amp, it will tip over. :)

    I suppose the plywood should be somewhat larger than the footprint of your amp, and you can adjust the inflation of the tube so it squashes down a fair amount. That way it doesn't have very far to tip before the plywood stabilizes it.
     
  17. Mcrelly

    Mcrelly

    Jun 16, 2003
    Minnesota, USA
    I work at Costco and they have, currently, "venture Products 8 pack anti-fatigue flooring mats" for $12.59. EIGHT 2' x 2' x 1/4" mats

    search venture products or anti-fatigue mats and you might find something similar.

    if you know someone with a costco membership, check it out!!!
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.