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Auralex Gramma For Removing Excess Rumbling?

PolkaHero

PolkaHero

Supporting Member
Jan 5, 2002
2,645
3,299
Michigan
#1
My bandmate discovered this product when he was at Sweetwater in Indiana. It is a board with acoustical foam underneath that you set your speaker cabinet on.

He A/B'd a bass amp with and without the Gramma and said the difference in sound was rather remarkable. He said it removes the "boominess" one confronts with hollow stages and certain halls without taking away from the overall lows.

Anybody here use or have tried this product? Is it worth the $50?
 
#3
I use a pair of these under my 8x10 Megaliath. They are excellent. They really do a great job tightening up the bottom end and making everything sound clearer in the low-mids. This is especially useful if you find yourself on a stage that is essentially a big, hollow box.

Sure, you could built something like this. But don't think for a second that this is some kind of cheap mattress foam. This stuff is made of special high density material specifically designed for this purpose. Aurelux is a leader in studio sound isolation systems.

To me it was definitely worth the $50 a pop.

You can also get them at Invalid Link Removed
 
#4
It's no 'miracle product', though. How it works is it isolates the cab from the floor preventing the floor help to bounce the lows out better. On some stages, it's probably very handy preventing muddy tone.
 
#5
I posted about 3 weeks ago asking if anyone knew anything about the GRAMMA. There are only 3 AURALEX dealers in all of Canada, but luckily 2 of them are in the GTA (Greater Toronto Area). I had to order them by the case though, but a buddy/co-worker of mine wanted to try three of them, so I lucked out! The price is really not that bad, and if it does what everyone says it does, including reducing room resonance/rattling, then it's perfect for my needs!!!:D :D :D
 
#7
I built one too! 3/4" plywood with outdoor carpet glued on top (you can find small scraps at a carpet place - a guy gave me a large piece gratis). For the foam on the underside I bought a $10 sleeping pad at Walmart - one of those roll-up camping pads about 5/8" thick - very dense foam. I glued one thickness onto the whole bottom area of the plywood using Weldwood contact cement (the kind you can brush on from a can). Then I laminated "feet" for the four corners and one for the center (about 5 X 5") using two additional cut thicknesses of the pad - again glued with contact cement.
The improvement in sound is really good on hollow wooden stages as mentioned above, but you can tell the difference in an A/B comparison on nearly any floor, even a concrete slab in my workshop. The caster idea is cool - I didn't do that.
G
 
#8
Originally posted by Donne Demarest
I just built myself an isolation platform.

3/4 high grade plywood
Black Paint or Carpet
Big Rubber Feet (2 5/8" and FAT)

Cost = next to nothing.

Option: Removeable 3" wheels (that clear the Feet) to do double duty.
Click to expand...

You get pretty good results from your homemade job, Donne?
 
#11
I'm thinking of using Donne's idea but also buying two 1'x1' sections of Auralex's Studiofoam(for a measly $6) and gluing those to the bottom of the board, then using a staple gun for carpet on the top.

The last wedding I played had a huge wooden stage. I had the bass control on my amp rolled off ALL THE WAY and the bass response was still more than the P.A. was producing!
 
#12
I got mine at the local Hardware Store.

When you start getting large they are known as
"Bumpers" and are manufactured for Trucks, Trailers, Cabinets, and other industrial app.'s.

PolkaHero's Idea is Excellent:

Originally posted by PolkaHero
I'm thinking of using Donne's idea but also buying two 1'x1' sections of Auralex's Studiofoam(for a measly $6) and gluing those to the bottom of the board, then using a staple gun for carpet on the top.
Click to expand...
 
#14
Originally posted by Tsal
It's no 'miracle product', though. How it works is it isolates the cab from the floor preventing the floor help to bounce the lows out better. On some stages, it's probably very handy preventing muddy tone.
Click to expand...

Excellent point. On some stages it may improve tone, on other stages it might degrade tone (sometimes it's better for the cab to couple w/the floor). But heck, it wouldn't be a huge inconvenience to carry one of those things around.
 
#16
Let us know how it performs on your gig, Groove M.D. I've given up on my project of building my own simply because I can't find the rubber feet to go on the bottom. I'll probably buy the real thing but just want to be sure I'm not wasting $50.
 
#18
Originally posted by GrooveDr
yo Polka, go get one! This thing definitely lives up to the hype! There's a door that usually rattles where we play when I hit certain notes...with the GRAMMA under my rig, we didn't hear it even once!!!:D
Click to expand...

Thanks for the report, Doc! I'm playing a bunch of weddings in the near future in various halls, and this might make a big difference in the acoustical problems that I'll face.:)
 

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