nitty gritty on sand vs. cement
Silica sand has a specific gravity around 2.67. Cement has a specific gravity of 3.15. The advantage (weight) of cement over sand would be 3.15/2.67. Sand is inert in comparison to cement. Cement is very alkaline. This alkalinity becomes active with the addition of water.
Cement particles are MUCH finer than sand, hence any miniscule openings in the cabinet could become avenues for leakage. IMHO cement has drawbacks besides being more expensive.
Mongo does concrete. Concrete is Mongo's life.
Talk with your local ready-mix provider. They have piles (tons) of sand. After dry weather there are several inches of "dry" sand available.
Silica sand has a specific gravity around 2.67. Cement has a specific gravity of 3.15. The advantage (weight) of cement over sand would be 3.15/2.67. Sand is inert in comparison to cement. Cement is very alkaline. This alkalinity becomes active with the addition of water.
Cement particles are MUCH finer than sand, hence any miniscule openings in the cabinet could become avenues for leakage. IMHO cement has drawbacks besides being more expensive.
Mongo does concrete. Concrete is Mongo's life.
Talk with your local ready-mix provider. They have piles (tons) of sand. After dry weather there are several inches of "dry" sand available.
Overd0se said:
There is a difference between Type1/2 cement. mortor or ready mix cement .
Type 1/2 cement is portland cement and does not have sand gravel or lime or clay mixed into it is just( Cement )and is very fine so it would fill in the voids more compactly or densely. As long as it is not exposed to moisture it will stay in it's powder stage . but that will be very hard to acomplish.
I am a Tile contractor and deal with this daily.
Just my 2cents.
Regards.
Craig.
Time out
I think some of you are missing the point about using sand which i mentioned earlier. Sure there are other materials, one being dry Portland cement powder that could be poured into the same cabinet wall gap and result in a wall that is denser than either straight sand fill or solid wood....but the other materials will not convert vibration to heat by friction. Increased density just gives you a lower frequency panel resonance, it does not reduce the amplitude of the resonance. With sand, one panel vibrates, the sand jiggles around through it's thickness and turns the micro-rubbing motions of all those little slippery grains of sand into heat. By the outer panel there is actually less vibration, plus the extra weight of the sand also, like the other fillers, lowers the resonant frequency. If you think a solid poured cast speaker box, you know where you mix the cement with sand, gravel and water and let it harden properly in a mold, is going to be resonance free, forget it. It will amaze you how well it will ring if you find it's magic resonant frequency. I've seen this in my own experiments and it didn't take much amplifier power either!
That point being clarified I think this discussion and some of the other ideas that are appearing is a good thing.
I think some of you are missing the point about using sand which i mentioned earlier. Sure there are other materials, one being dry Portland cement powder that could be poured into the same cabinet wall gap and result in a wall that is denser than either straight sand fill or solid wood....but the other materials will not convert vibration to heat by friction. Increased density just gives you a lower frequency panel resonance, it does not reduce the amplitude of the resonance. With sand, one panel vibrates, the sand jiggles around through it's thickness and turns the micro-rubbing motions of all those little slippery grains of sand into heat. By the outer panel there is actually less vibration, plus the extra weight of the sand also, like the other fillers, lowers the resonant frequency. If you think a solid poured cast speaker box, you know where you mix the cement with sand, gravel and water and let it harden properly in a mold, is going to be resonance free, forget it. It will amaze you how well it will ring if you find it's magic resonant frequency. I've seen this in my own experiments and it didn't take much amplifier power either!
That point being clarified I think this discussion and some of the other ideas that are appearing is a good thing.
dry friction vs viscous damping
I've been following this thread for a while, and it got me to thinking... I was only going to reply if I had an idea for good dry sand, or something better- but now I've just got a question!
How about jello? Not literally jello, but are there any speaker designs that anybody could name that use double walls with a viscous damper between them? For example, if you mixed the sand with petrolium jelly before putting it between the cabinet walls...
I am thinking that you would first need some stiff walls to raise their resonant frequency, then a viscous damper (some sort of gel?) and then a heavy wall....?
just thinking. I haven't heard how (good) a double walled sand damped enclosure sounds. One of these days I'l have to try it.
I've been following this thread for a while, and it got me to thinking... I was only going to reply if I had an idea for good dry sand, or something better- but now I've just got a question!
How about jello? Not literally jello, but are there any speaker designs that anybody could name that use double walls with a viscous damper between them? For example, if you mixed the sand with petrolium jelly before putting it between the cabinet walls...
I am thinking that you would first need some stiff walls to raise their resonant frequency, then a viscous damper (some sort of gel?) and then a heavy wall....?
just thinking. I haven't heard how (good) a double walled sand damped enclosure sounds. One of these days I'l have to try it.
Look at:
http://users.skynet.be/accupulse/manger_head.html
scroll down to about 3/4 of the page
Regards
Charles
Sorry for bringing up this old tread.
I am about to build small DIY speaker stand which will be placed on a working desk.
Stand Size: 15.5cm (W) x 23cm (H) X 21cm (D)
I'm thinking if I should just make a wooden/acrylic Cubical box and fill it with sand or other mentioned materials from the above posts? will that work? any concerns?
I am about to build small DIY speaker stand which will be placed on a working desk.
Stand Size: 15.5cm (W) x 23cm (H) X 21cm (D)
I'm thinking if I should just make a wooden/acrylic Cubical box and fill it with sand or other mentioned materials from the above posts? will that work? any concerns?
Sand options ...
Garnet sand has a significantly higher density than silica (quartz / "ordinary" sand). Garnet sand is used as a grit blasting abrasive, so you could track down a supply that way.
If you have access to a metal foundry, you could also consider chromite sand or zircon sand, both of which are also much higher density than silica. No silicosis risk, either. If you buy a sack of the stuff, it WILL be dry, as foundries specify this when then purchase it. (For those who wish to know why, the water interferes with the chemistry of the binders used in foundries mould and/or core making.)
All are more expensive than regular silica sand, but if getting maximum density is the object, then hey, go for it.
One last thing: Closely sized sand - of whatever type - will not pack densely. Filling the interstices between large grains requires smaller grains, and so on.
cheers
Doug (ex foundry metallurgist.)
Garnet sand has a significantly higher density than silica (quartz / "ordinary" sand). Garnet sand is used as a grit blasting abrasive, so you could track down a supply that way.
If you have access to a metal foundry, you could also consider chromite sand or zircon sand, both of which are also much higher density than silica. No silicosis risk, either. If you buy a sack of the stuff, it WILL be dry, as foundries specify this when then purchase it. (For those who wish to know why, the water interferes with the chemistry of the binders used in foundries mould and/or core making.)
All are more expensive than regular silica sand, but if getting maximum density is the object, then hey, go for it.
One last thing: Closely sized sand - of whatever type - will not pack densely. Filling the interstices between large grains requires smaller grains, and so on.
cheers
Doug (ex foundry metallurgist.)
Hey Doug,
thanks for the info.
I am able to source The Zircon Sand:
Zirconium Powder-Zirconium Powder Manufacturers, Suppliers and Exporters on Alibaba.com
I am located in Hong Kong, and so I can obtain it easily. Should I mix it with other kind of sand just to increase the density?
And how about the stand enclosure? Should I use Wood? I want to use acrylic (better looking), but not sure if it's gonna work well.
again, really appreciate your input!
thanks for the info.
I am able to source The Zircon Sand:
Zirconium Powder-Zirconium Powder Manufacturers, Suppliers and Exporters on Alibaba.com
I am located in Hong Kong, and so I can obtain it easily. Should I mix it with other kind of sand just to increase the density?
And how about the stand enclosure? Should I use Wood? I want to use acrylic (better looking), but not sure if it's gonna work well.
again, really appreciate your input!
Pano, kitty litter is definitely easier to obtain. I should get some tomorrow before the holiday starts.
Eric, thats a good point, I will order thick acrylic tomorrow.
Here are the combos I will try out in the coming weeks:
1. thick acrylic + kitty litter
2. thick acrylic + Zircon sand
3. Wood (undecided on what type of wood yet) + Zircon
4. Wood (undecided on what type of wood yet) + Kitty litter
Eric, thats a good point, I will order thick acrylic tomorrow.
Here are the combos I will try out in the coming weeks:
1. thick acrylic + kitty litter
2. thick acrylic + Zircon sand
3. Wood (undecided on what type of wood yet) + Zircon
4. Wood (undecided on what type of wood yet) + Kitty litter
sand for speakers
Sad to say, but I'm somewhat of an expert on the properties of sand...what you want is mortar sand. It is somewhat smaller in size, and has sharp edges and shape. When you tumble, mix or blend mortar sand, it compacts and the pieces"lock" together. This characteristic means that you want to agitate it as you put it in your speaker cavity. In other words, shake the cabinet to get it to settle.
If you could find one of those industrial or laboratory shakers to set your speaker on, it would work quite well. Of course, the weight of your speaker is going to determine if the shaker could handle it. There are industrial skakers that are huge.
No matter what sand you get, put it in an old pan and bake it for a hour at 500 degrees F. Take the pan out at 30 minutes and shake it to redistribute the sand. I would buy bagged sand only. It is cheap.
Sand that is dripping wet is about 6-6% moisture. All of the water is held externally; it is free water, so it dries easily.
Sad to say, but I'm somewhat of an expert on the properties of sand...what you want is mortar sand. It is somewhat smaller in size, and has sharp edges and shape. When you tumble, mix or blend mortar sand, it compacts and the pieces"lock" together. This characteristic means that you want to agitate it as you put it in your speaker cavity. In other words, shake the cabinet to get it to settle.
If you could find one of those industrial or laboratory shakers to set your speaker on, it would work quite well. Of course, the weight of your speaker is going to determine if the shaker could handle it. There are industrial skakers that are huge.
No matter what sand you get, put it in an old pan and bake it for a hour at 500 degrees F. Take the pan out at 30 minutes and shake it to redistribute the sand. I would buy bagged sand only. It is cheap.
Sand that is dripping wet is about 6-6% moisture. All of the water is held externally; it is free water, so it dries easily.
Indeed shaking the container of sand will help it settle and increase the density a little.
If you don't have a shaker - and the size/shape of your speaker boxes permit - you could just load them into (or onto) your car and take them for a drive. The road vibration should be enough to give a gentle shake.
Doug
Do a search for "Urn Sand".
It's the ultra-fine white sand used for snuffing-out cigarettes. It has the right particle size for energy loss and moisture resistance for this application. (..it's also a "dry-type" sand that contains no organisms, and is large enough in particle size to minimize air-born pollution when pouring it.)
In addition:
Generally cover those surfaces that will be in contact with the sand with a fairly thin compliant layer (..a thinned-out solution of wood glue "rolled-on application" + fabric). This further helps with energy loss and damping, and removes any potential "buzzing" from some unexpected voids. My fabric of choice is cheap flannel sheets, which seem to be about right.
It's the ultra-fine white sand used for snuffing-out cigarettes. It has the right particle size for energy loss and moisture resistance for this application. (..it's also a "dry-type" sand that contains no organisms, and is large enough in particle size to minimize air-born pollution when pouring it.)
In addition:
Generally cover those surfaces that will be in contact with the sand with a fairly thin compliant layer (..a thinned-out solution of wood glue "rolled-on application" + fabric). This further helps with energy loss and damping, and removes any potential "buzzing" from some unexpected voids. My fabric of choice is cheap flannel sheets, which seem to be about right.
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People who did sand blasting for a living, if they did it long enough were subject to silicosis. However, there is a man made product, media that is clean straight out of the bag. KLEEN BLAST dust free copper slag.
wow, didn't expect there are so many choices of sand. I will see what I can get later today, as most of the shops are already closed for the CNY holiday.
I've ordered the enclosure made with 1.8cm thickness, transparent acrylic. Maybe I can use wood or marble next time - but those requires custom orders and takes more time to deliver.
Do you think solid marbles will work too?
I've ordered the enclosure made with 1.8cm thickness, transparent acrylic. Maybe I can use wood or marble next time - but those requires custom orders and takes more time to deliver.
Do you think solid marbles will work too?
Form follows function.
I believe the main value of sand filled speaker panels is to have the sound energy absorbed by the friction in the sand cavity to keep that sound energy from going into the room. With this model, you would want a sand composition more like slightly different size balls that continue to micro-bunce, instead of sharp edged grains that lock together after continued vibration. With this model, would pool filter sand be one good option, since it is mixed to allow continuous water flow.
You would probably want to roll on a couple thick coats of primer paint on all internal panel surfaces to block future moisture bleed through.
Should you turn your speaker upside down every now and then to loosen up packed sand areas?
I believe the main value of sand filled speaker panels is to have the sound energy absorbed by the friction in the sand cavity to keep that sound energy from going into the room. With this model, you would want a sand composition more like slightly different size balls that continue to micro-bunce, instead of sharp edged grains that lock together after continued vibration. With this model, would pool filter sand be one good option, since it is mixed to allow continuous water flow.
You would probably want to roll on a couple thick coats of primer paint on all internal panel surfaces to block future moisture bleed through.
Should you turn your speaker upside down every now and then to loosen up packed sand areas?
haha, actually I am making a pair of speaker STANDs, not the speaker enclosure.
the speakers I am using are Mark & Daniels mini+
the enclosure is made of marble
more info here Mark & Daniel manufacturer and distributor of high end speakers including the Maximus, Aragorn, Apollo, AMT Dreams drivers
the speakers I am using are Mark & Daniels mini+
An externally hosted image should be here but it was not working when we last tested it.
the enclosure is made of marble
more info here Mark & Daniel manufacturer and distributor of high end speakers including the Maximus, Aragorn, Apollo, AMT Dreams drivers
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