Physics majors - What base is more stable: pedestal or tripod/quadpod? (speaker stands)

[MichaelD]

*EDIT*
Link fixed. Stupid Geoshities.

It has been said more than once that "The collective knowledge of all mankind can be found in ATOT." Let's see, shall we?

I'm building speaker stands. Exactly like these, here.

They are made of PVC pipe. You fill the pipe with sand to damp the sound (keep the stands from vibrating) and keep them from tipping.

Notice the bases are rectangular. I've seen some stands that have the base cut out in a tripod or quadpod shape...no pics, but you can figure it out. Three or four "legs" as opposed to one rectangular/square piece.

What configuration is more stable? The speakers that will be on them are slightly bigger. These

Here's a link to the whole DIY page. I think these stands are just the Cat's Pajamas. :wine: About a whole $40 in materials, that's it.

Thanks!

 

[Howard]

On a flat surface, probably the pedestals. They have a lot more weight at the very bottom.

 

[FoBoT]

if the floor is flat, like tile/wood, then a flat base of any shape should be fine.

if you are putting them on carpet, especially a shag, i would think individual legs would do better at the smaller area will "dig in" to the abnormal surface better

 

[WinkOsmosis]

Draw an inscribed circle on the bases. Whichever base has the biggest diameter is the most stable, since that is the smallest radius from the center, and the one that determines stability.
I'm a liberal arts major though.

 

[Amused]

A side note: If you are using these on carpet you'll want to use pointy spikes for feet. Just like the ones most high end tower speakers come with.

 

[MichaelD]

Thanks guys. I will indeed be using them on carpet. I plan on putting spikes on the feet no matter what shape base I choose.

 

[Entity]

Originally posted by: FoBoT
if the floor is flat, like tile/wood, then a flat base of any shape should be fine.

if you are putting them on carpet, especially a shag, i would think individual legs would do better at the smaller area will "dig in" to the abnormal surface better

Keep an option open for "spikes," if you haven't considered it already. My towers (Dahlquist QX10) came with a set of spikes that make them amazingly stable on an ugly shag pile carpet (not my choice; it's a rental). My stands don't have that stability, but the towers do.

Edit: Damnit, you posted about carpet and spikes before I finished typing.

Rob

 

[Amused]

Originally posted by: Entity

Originally posted by: FoBoT
if the floor is flat, like tile/wood, then a flat base of any shape should be fine.

if you are putting them on carpet, especially a shag, i would think individual legs would do better at the smaller area will "dig in" to the abnormal surface better

Keep an option open for "spikes," if you haven't considered it already. My towers (Dahlquist QX10) came with a set of spikes that make them amazingly stable on an ugly shag pile carpet (not my choice; it's a rental). My stands don't have that stability, but the towers do.

Edit: Damnit, you posted about carpet and spikes before I finished typing.

Rob

 

[Spencer278]

The liberal arts major is correct when the center of mass pass out side of the circle the speakers are going down the weight of the bass will almost be irrelevent. A true tripod type design would provide much greater stablitly but take up more space having three legs coming down but most of the advatage you would gain would be from the added wieght.

 

[EvilYoda]

Well, the heavier weight is why I went with the design that I did for my speaker stands...almost the same as the TNT original, but with 3 2" PVCs.

You can take a look here...it's not a very good picture, but you get the idea. Still have to add some "feet" (spikes) on the corner, but it's not a huge deal in the basement since the carpet is really tight and right ontop of the cement.

 

[MichaelD]

Wow, EVILYODA, those are some NICE stands. Nice speakers too. :Q A bit out of my price range, though.

I would imagine that three 2" tubes full of sand are heavier than a single 4" tube full of sand.

I hadn't thought of staining them. They match your FlexyRack perfectly. That looks great too, BTW.

Thanks for the pics...you've given me some new ideas to work with.

 

[WinkOsmosis]

Originally posted by: MichaelD


I would imagine that three 2" tubes full of sand are heavier than a single 4" tube full of sand.

Not according to my calculations..
Volume of the cylinders varies with area of the circles. Area of a circle is pi*r^2.
3*pi*(2)^2 = 12pi
pi*(4)^2 = 16pi

 

[Joony]

mount it on the floor for ultimate stability

 

[MichaelD]

Originally posted by: WinkOsmosis

Originally posted by: MichaelD


I would imagine that three 2" tubes full of sand are heavier than a single 4" tube full of sand.

Not according to my calculations..
Volume of the cylinders varies with area of the circles. Area of a circle is pi*r^2.
3*pi*(2)^2 = 12pi
pi*(4)^2 = 16pi

Ah. And now you know why I failed math. Twice. In three years. 2+2=4. Other than that, I'm pretty lost. Thanks, Wink-O.

 

[Howard]

You may want to give some thought to bathing the sand in water or oil.

Just make sure it's leakproof, LOL.

 

[MichaelD]

Originally posted by: Howard
You may want to give some thought to bathing the sand in water or oil.

Just make sure it's leakproof, LOL.

Believe me, that crossed my mind. I can imagine my living room floor covered in sand. Hell, I've seen it covered in sawdust a few times already...not pretty.

Anyone who has taken their car/truck to the beach knows that sand NEVER comes out of the carpet, no matter what Megawatt Zoot vacuum cleaner you use.

I asked a lot of questions on the DIY forums about this. It's solved this way.

You cut a circle the diameter of the PCV into the base/top of the stand. About 1/2 way into the wood. Put a ring of wood glue/silicone around the inside edge of the ring. The pipe then actually sits INSIDE the wood instead of on top of it.

What physically keeps the stand together is a 5/8 or 3/4" piece of threaded rod secured with nuts, top and bottom. An ingeniously simple design, really.

 

[xyion]

Originally posted by: WinkOsmosis

Originally posted by: MichaelD


I would imagine that three 2" tubes full of sand are heavier than a single 4" tube full of sand.

Not according to my calculations..
Volume of the cylinders varies with area of the circles. Area of a circle is pi*r^2.
3*pi*(2)^2 = 12pi
pi*(4)^2 = 16pi

true that the 4" tube is heavier, but the 3 2" tubes will privide greater stability because you spread them out, increasing the radius of stability(as you mentioned before). Its much harder to knock over a tripod then a single column.

 

[MichaelD]

Originally posted by: xyion

Originally posted by: WinkOsmosis

Originally posted by: MichaelD


I would imagine that three 2" tubes full of sand are heavier than a single 4" tube full of sand.

Not according to my calculations..
Volume of the cylinders varies with area of the circles. Area of a circle is pi*r^2.
3*pi*(2)^2 = 12pi
pi*(4)^2 = 16pi

true that the 4" tube is heavier, but the 3 2" tubes will privide greater stability because you spread them out, increasing the radius of stability(as you mentioned before). Its much harder to knock over a tripod then a single column.

Hmm. Another Physics dude checks in. And I'm checking him out. [powers]Well, not LITERALLY...I don't swing that way, baby.[/powers]

I do plan on putting spikes on the bottom of the pedestals, so that should help. The stands will be about 20-24" tall, so stability shouldn't be too hard to acheive...I think.

AFA how many "columns" to have...it all boils down to aesthetics, I think. Three columns will be a PITA to clean...looks nice, though.

 

[EvilYoda]

Originally posted by: MichaelD
Wow, EVILYODA, those are some NICE stands. Nice speakers too. :Q A bit out of my price range, though.

I would imagine that three 2" tubes full of sand are heavier than a single 4" tube full of sand.

I hadn't thought of staining them. They match your FlexyRack perfectly. That looks great too, BTW.

Thanks for the pics...you've given me some new ideas to work with.

np...I'm just here to spread the joy. As for my speakers...yeah, I love my babies. It'll also explain why I'm a poor college student.

BTW, the color of the wood on the stands and the flexy rack aren't a stain, it's the cheap vinyl laminate from PE! Fooled ya, eh? It's really easy to work with, for only $10 a tube. (One tube covered the entire rack) The only thing about DIY is that you start thinking about "what else can I make"...I think I'm going to make a rack for my DVDs right now, but a little different from your normal stuff, since I'm only using up the leftover MDF.

Good luck, and feel free to PM with any ?s.

 

[xyion]

Originally posted by: MichaelD

Originally posted by: xyion

Originally posted by: WinkOsmosis

Originally posted by: MichaelD


I would imagine that three 2" tubes full of sand are heavier than a single 4" tube full of sand.

Not according to my calculations..
Volume of the cylinders varies with area of the circles. Area of a circle is pi*r^2.
3*pi*(2)^2 = 12pi
pi*(4)^2 = 16pi

true that the 4" tube is heavier, but the 3 2" tubes will privide greater stability because you spread them out, increasing the radius of stability(as you mentioned before). Its much harder to knock over a tripod then a single column.

Hmm. Another Physics dude checks in. And I'm checking him out. [powers]Well, not LITERALLY...I don't swing that way, baby.[/powers]

I do plan on putting spikes on the bottom of the pedestals, so that should help. The stands will be about 20-24" tall, so stability shouldn't be too hard to acheive...I think.

AFA how many "columns" to have...it all boils down to aesthetics, I think. Three columns will be a PITA to clean...looks nice, though.

Technically I'm an Electrical Engineer, but I've had far too many physucks classes. Anyway, I'm sure that 1 column will support it just fine, I was just saying that 3 would be more stable. The height of the speakers also plays into this, but i'm sure you'll do a good bit of testing before finalizing anything.

 

[MichaelD]

Dear Mister E.E.

The speakers are 20" high. These.

 

[MichaelD]

Originally posted by: EvilYoda

Originally posted by: MichaelD
Wow, EVILYODA, those are some NICE stands. Nice speakers too. :Q A bit out of my price range, though.

I would imagine that three 2" tubes full of sand are heavier than a single 4" tube full of sand.

I hadn't thought of staining them. They match your FlexyRack perfectly. That looks great too, BTW.

Thanks for the pics...you've given me some new ideas to work with.

np...I'm just here to spread the joy. As for my speakers...yeah, I love my babies. It'll also explain why I'm a poor college student.

BTW, the color of the wood on the stands and the flexy rack aren't a stain, it's the cheap vinyl laminate from PE! Fooled ya, eh? It's really easy to work with, for only $10 a tube. (One tube covered the entire rack) The only thing about DIY is that you start thinking about "what else can I make"...I think I'm going to make a rack for my DVDs right now, but a little different from your normal stuff, since I'm only using up the leftover MDF.

Good luck, and feel free to PM with any ?s.

Whoa. That's VINYL? :Q I can't tell. Great job! How'd you get the edges to look so perfect? That's the hardest part. Do tell.

 

[xyion]

$400 for speakers :Q

I spent like $50 on my entire "surround sound" system. Anyway, since the speakers are shorter than the stand, I'm sure a 4" tube will work fine (not cruching any numbers here), especially if it were done before. However, you can be sure that a 3+ column stand will work better. Its harder to balance something on a single column vs a number of them. Also, don't use 2 columns, either 1 or 3+. I'm betting you dont have to worry about them being knocked around like I would, so the single column just may be perfect.

EDIT: now that I looked that the stand you were planning on building closely, if your speakers are like the ones in the picture 1 column would be absolutely alright.

 

[EvilYoda]

heh...lots of practice. I made sure that my earliest attempts were on corners that would end up on the back, facing the wall. It's not that hard, really, you just have to figure out a good method and take your time. Luckily, I have good hands, and I'm a perfectionist, so it came out well. There are still a few things I'd change, but oh well, I'm happy with how things turned out.

BTW, reading what you said earlier...it's much easier if you just drill all the way through one layer of wood and then glue that to the other piece (this is why most DIY stands have two layers), thus giving you the same final product w/o having to worry about drilling perfectly x" into a piece of wood. It's a good thing I went with 3 tubes too, since my friend didn't have a 4" hole saw.

finally going to sleep...I'll see how the thread's doing in the morning.

 

[MichaelD]

The chance of them getting knocked over is very slim.

No kids.
No dogs.
No cats.

Just one bigass clumsy person living there. Me. :Q I may velcro the speakers to the stand, just as extra insurance. I want to bounce that idea around at the H/T forums to see if it would have any kind of detrimental effects.