Granite on Powered Subwoofer

[reju]

Hi,

I had purchased Polk microPRO 1000 about couple of months back and I am happy with its performance, as it delivers very deep and powerful bass.

But sometimes when I play source with some heavy bass, and at higher volumes, the sub used to move around the floor, say 4-5 inches! Even though the sub weighs about 15 kgs this would happen! I have placed it on marble floor. I have tried adjusting the rubber feet and once even stuck them to the floor using powerful double sided 3M tapes. But still no luck!

So then I struck upon this idea of placing some good weight on the sub to prevent it from dancing around. At the same time it should look neat.

So these are two granite slabs of approx 17-18mm each, joined together and edges moulded. Total weight is about 10kgs. I have placed it on a non-skid grey coloured rubber mat. I have spent Rs. 650.00 and it's working like a charm. The sub stays put now. I am not sure if it has done any good or bad to the sound quality. hyeah:

I would be happy to receive comments from experts on how good or bad this idea is? Thanks.

 

[gobble]

Granite resonates at low frequencies

The Singing Pyramid - Alternative History Articles - The Book Of THoTH
The Official Robert Bauval Website -PYRAMID OF SECRETS THE SINGING PYRAMID AND THE MYTH OF CREATION By Alan Alford

HTH

Cheers

 

[reju]

So good or bad?

 

[sud98]

I suppose bad. Although granite block, I am told is good to be kept on devices to add as a damping device.

You can try the following products

Amazon.com: Auralex SubDude Subwoofer Isolation Riser; 15x15x2-inch SubDude in Charcoal, Single: Musical Instruments

Group member santhol2 has bought these so you can check his opinion.

 

[reju]

I had read about some people placing sub on top of granite for isolation, rather than the other way around. But I feel they maybe having carpet or wooden floors, hence the requirement? In my case I have marble floor.

But the "Subdude" product has some foam layer which may work to solve my problem?

 

[soulforged]

You can try placing the granite slab on top of a cork sheet...say 5mm or so thick...might help...

 

[Thad E Ginathom]

It looks extremely classy.

Might be some problem, though, with the uninitiated sitting on it!

 

[midnitefreakin]

buy a rug which is fluffy and plc the sub on it...i did the same for my friends with good effects ...try it out....

 

[Thad E Ginathom]

To my physics-failed mind, the more weight the better, and this lump of rock is certainly going to add weight. As well as good looks

 

[spirovious]

Can putting Sub on Rubber mat help?

 

[arj]

Reju, it is a very good idea. this has been used very often on speakers also as a damping mechanism.
if you are too worried about damping, just paste a thin wood layer OR Cork layer below the granite. but I do not think that would be necessary as the piece you have put is thick enough.

Also to my best understanding Granite rings at high freq and not low !

 

[shershah]

buy a rug which is fluffy and plc the sub on it...i did the same for my friends with good effects ...try it out....

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[Thad E Ginathom]

Also to my best understanding Granite rings at high freq and not low !

Again, I admit to having scraped through my physics exam at school by some guesswork, but --- doesn't it depend on the size/mass/something of the piece of granite?

 

[midnitefreakin]

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didnt get it

hope some error!

 

[Kittu]

didnt get it

hope some error!

May be he is seconding your opinion very strongly

 

[venkatcr]

Santhosh and I got the GRAMMA version from Auralex. This isolates the sub from the floor reducing transfer of resonance through the floor to other items in the room. It has also made my sub tighter, making it merge seamless with the other speakers.

Since th GRAMMA completely isolates the sub from the floor, I assume it should also stop it from dancing.

Cheers

 

[reju]

Now I tried some music with lot of bass and and kept sub volume to the max on AVR and sub, the sub still moved about 1 cm. It also gave out some loud vibrating sound. (This sound comes even without the granite). Is this sound normal for all subwoofers if driven they are driven at the max volumes?

 

[midnitefreakin]

May be he is seconding your opinion very strongly

hehe..wow

 

[reju]

Santhosh and I got the GRAMMA version from Auralex. This isolates the sub from the floor reducing transfer of resonance through the floor to other items in the room. It has also made my sub tighter, making it merge seamless with the other speakers.

Since th GRAMMA completely isolates the sub from the floor, I assume it should also stop it from dancing.

Cheers

How about using thick heatlon sheet in between the floor and a granite slab and placing the sub over the granite slab?

 

[venkatcr]

How about using thick heatlon sheet in between the floor and a granite slab and placing the sub over the granite slab?

I am not sure. What Auralex has done is to use the same material they use with bass traps as the legs and some spacial board on top to absorb the sound.

BTW, you should not get any vibratory sound with a good sub.

Cheers