Building a clone to the Auralex Gramma

[sud98]

From the past few weeks I have been using a borrowed (from Santhosh) the Auralex Gramma for my subwoofer (Product Review - Auralex GRAMMA).

The effect esp. in heavy subwoofer scenes is quite good, like the depth charges scene in U571.

However, for the price 59 USD plus the cost of shipping it, I think one can build an el cheapo version of the same. Since, asking someone to carry this is a bit difficult (as its fairly big) and shipping costs around 50-60 USD.

So, I am thinking of using something like this

1. Use a base of granite - I believe this will be better than wood with carpet layer or even marble as its a soft stone. I believe, the cost of a 3 ft by 2 ft of granite should be around 600-1000 Rs. Correct me if I am wrong?

2. The second thing I liked of the Auralex was the foam like thing in the bottom which is a good isolator but I am not sure. Is this some thing available in stores?

Will putting the granite slab on the floor make it worse?

Let me know your thoughts and suggestions.

 

[jls001]

Will 3 (or 4) brass cones also not perform the same job of decoupling the sub to the floor? I am asking, I don't know

 

[sud98]

I would ideally want to use something that is easily available.

My logic (I maybe wrong) that unlike speakers, spikes dont work well with subs, so its better to use thick absorbent material to isolate than cones.

So my guess is that that a thick granite slab by itself will be better than brass cones. But if the acoustic foam is available, then it will be probably be better.

 

[jls001]

Slate may work better at decoupling than granite and marble. Sandstone would also be a better option than either. People have used slate for equipment rack and also to build turntable plinths because of of its property of vibration absorption. As far as I know, granite will produce a "ring".

BUT, if you are also going to use additional absorbent layers (say, some sort of foam or gel layer or even thermocole), granite may work well.

 

[santhosh]

Sudhir, glad you liked the Gramma and that scene from U571 really rocks the house.
I think you should go for an absorbent yet rigid material rather than stone. Anutone makes a nice high density wood well board that they use for treating ceilings. IMO, you should try and use that.

 

[sud98]

Where can I get slate? Is it something easily available?

Anyone specific in Anutone to discuss with. Since they may not be too keen in a small value deal. Its not in their product portfolio.

 

[ruenigma]

We may want to involve @magma in this discussion. He'll definitely add more value from his experience.