Granite on Powered Subwoofer

[Thad E Ginathom]

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?

Shouldn't as sub be kept at barely audible level. turn it up until you can hear it and then turn it back a touch is the advise I always heard, but I do not want more bass in my music, I want more treble, so I don't know.

Your sub troubles (sub trubs?) is reminding me of some of the reported difficulties with washing machines, in the domestic-appliance thread over on Team-BHP! Come to think of it the same answer might be relevant ... make sure it is level, and the weight is even on all four feet. Are your sub feet adjustable? can you feel any vibration at one or two corners?

 

[venkatcr]

Your sub troubles (sub trubs?) is reminding me of some of the reported difficulties with washing machines, in the domestic-appliance thread over on Team-BHP! Come to think of it the same answer might be relevant ... make sure it is level, and the weight is even on all four feet. Are your sub feet adjustable? can you feel any vibration at one or two corners?

Thad I have seen many subs dance. For example the Martin Logan subs actually move over 6-12 inches and you really have to run to catch them. This is the down firing variety, Fortunately you can convert most ML subs to front firing and then the dancing stops.

I always advice people to buy a small and thick rug and place down firing subs on that.

Cheers

 

[Kittu]

How about keeping a rubber mat under the SUB..?

 

[reju]

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

You mean even at full blast the subs should not produce any vibratory sounds? Does anyone else have the same experience?

I have read some people placing granites slabs underneath the subs as the carpet/ wooden floors were not suitable?

Maybe I should get a heatlon sheet and experiment!

 

[midnitefreakin]

You mean even at full blast the subs should not produce any vibratory sounds? Does anyone else have the same experience?

I have read some people placing granites slabs underneath the subs as the carpet/ wooden floors were not suitable?

Maybe I should get a heatlon sheet and experiment!

Y don't u start experimenting with stuff available at home? try ur rug, old carpet, cushion, old blanket, if any of it works then y invest in other items?

I am sure u will get desired result from one of them

 

[Thad E Ginathom]

rug underneath; granite on top.

Sounds like good ideas to me!

 

[arj]

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?

it does..size also affects resonant frequency..also granite is a confusing material since being an igneous rock , its composition varies and hence does not have just 1 consistent property

 

[arj]

in my experience with subs..you need to keep them as Stable as possible such that they are Coupled to the floor. I am sceptical about Rugs though..granite under should also be good. Granite over the sub increases the mass and hence couples it well to the floor as well.

last thing to put is a rubber mat under it ! you can put the rubber mat above the sub and sandwiched between the granite if you want...it makes for a constrained layer damping whicn is very good


in the end positioning of the sub is far more important than damping it...if you can "Couple" it to the room acoustically you will get fantastic results...else it will end up being a boom box

 

[shershah]

it does..size also affects resonant frequency..also granite is a confusing material since being an ingenious rock , its composition varies and hence does not have just 1 consistent property

Igneous rock?

 

[arj]

Igneous rock?

yup...corrected my typo !

 

[Thad E Ginathom]

But... I much prefer ingenious! :lol:

Thanks, arj, and thanks shershash, for preserving a perfect gem of typo for posterity.

I love a good typo. Unfortunately, I make only bad ones!

About the stone and the frequency, I asked myself, "If I carved bells out of this, assuming they rang at all, wouldn't the little ones would be higher frequency than the big ones?"

 

[reju]

My Mumbai made Auralex @ Rs. 350.
No more dancing. Good sound!!

 

[venkatcr]

Wow! That looks very close to what the original is. How in God's name did you make that? What is the material used?

Cheers

 

[reju]

I have attached couple of pictures to show how simple it is.

I went to this guy who makes car speaker cabinets and told him my requirement.

We used 14"x15" 18mm MDF base, covered with black carpet cloth. I had separately purchased 0.5m length 13mm heatlon sheet (Rs. 75). Couldn't find any thicker. So cut 4x 4" strips and pasted one above other to make it 2" heatlon blocks x 02 to be pasted at the bottom. Paid the guy Rs. 300.00

 

[midnitefreakin]

then y dont you remove the granite?

 

[reju]

then y dont you remove the granite?

As member arj has pointed out, adding mass should make it more stable and seat firmly on the isolater. So it should work out well. Also now that I have already spent Rs 650 on it, might as well use it

 

[Kittu]

As member arj has pointed out, adding mass should make it more stable and seat firmly on the isolater. So it should work out well. Also now that I have already spent Rs 650 on it, might as well use it

Well nothing beats the idea if you like the sound . Keep it . It looks good too.Why dont you keep a flower vase on top ? :lol:

 

[reju]

Well nothing beats the idea if you like the sound . Keep it . It looks good too.Why dont you keep a flower vase on top ? :lol:

Flower vase will unfortunately add vibrations. So decided against it

 

[venkatcr]

Good job, Reju. You have completed at 350 what the local dealer is charging 7500 for.

Cheers

 

[Thad E Ginathom]

It looks very nice to me. Covering the ? heatlon (haven't heard of it before) in the carpet, as well as the wood, would have added even more luxury.

Good looks and effectiveness: who could ask for more?

Well, those who want a base for a flower vase could, I suppose ... but i think it is quite right to veto this on grounds of danger of water as well as vibration.