Speaker stands

Jstas

A new set, more refined than my first time.

These are for the GF's house. Got a home theater assembled for her and her kids.

Would have just hung stuff but she's renting so stands it is.

JBL speakers courtesy of Mr. Grand. Whom I have to stop by and see as it's been a while.

skrol

They look nice. What are the verticals made from? Are they weighted (sand filled)?

rooftop59

looks good man! Looks like pvc pipe spray painted, so it probably can be filled,

GF with kids, I think that's awesome. Hope it works out! I am sure that the kids will love the gift, that can't hurt!!!

Jstas

PVC pipe? Really?

In iron floor flanges?

It's black pipe, cleaned, degreased and painted with an oil rubbed bronze paint.

The tops and bottoms were made with some left over oak plywood I had from another project I built for her kids and it has shelf edge molding to cover the plywood ends. I think all the materials including paint, stain and polyurethane, cost me $230 for all 4.

@skrol the stands are pretty heavy due to the black pipe. I was going to fill them half way with shot but I think I'm holding off for now. The tops come off easy, though so I can fill them easily too if they need more ballast. They don't really vibrate as is so the only thing shot/sand will do is to add stability.

They are about 26 inches tall which puts tweeters at the perfect height for ear-level while sitting on a couch.

Jhayman

Nice work..look Great

Jstas

nbrowser wrote: »

Jstats, nicely done and if I may say, overbuilt but that's NEVER a bad thing!

I don't think they are over-built. It's only 1" pipe. I wanted 2" pipe but the flanges would have been too big for the top and bottom panels. Each stand weighs about 11.5 pounds. They wobble a bit on carpet but that's 'cause they have rubber feet for hardwood floors.

I built them heavy on purpose with a wide base so they were less likely to tumble over 'cause kids, in general, are morons and no matter how many times you tell the little idiots not to horse around near heavy/expensive stuff, the little jerks don't get it until they hurt themselves and/or break something expensive. So I made them to help prevent them from being knocked over or falling on one of their precious, little heads thereby causing brain damage and making them stupider than they already are.

But a flimsy stand doesn't do much good sonically. It doesn't have the weight or rigidity to resist vibration. The reason people fill stands with sand or shot is because they are trying to reduce resonances and isolate the speaker from the surrounding environment by increasing the density of the stand and making it harder to vibrate. But if the stand is flimsy to begin with, it will not be able to control it's own weight let alone that of the speaker. It's like sticking a 426 HEMI between the frame rails of a Chevette without any extra bracing to handle the weight and power. Under load, that Chevette is going to shiver, shimmy and shake driving down the road and never drive straight either because the engine makes way more power and has way more weight to control that the Chevette frame was ever engineered to handle. Same goes for speaker stands. They need to be able to handle the weight and power output to stay sonically dead and isolate the drivers without transferring energy to the floor. Tower speakers are usually designed by the manufacturer to do just that. However, bookshelf speakers often lack the ability to not transfer resonances just by sheer size restrictions. So stands are used because, well, bookshelves are actually horrible places to stick speakers.

Stands should be sonically dead. It should be like you just placed that speaker on a section of floor that was taller than the rest of the surrounding floor.

You can do that by making the stand heavier than what the energy produced by the speaker can vibrate or you can make the stand with materials that have resonance reducing properties.

The point of sand and shot is that the sand grains or shot pellets have a large surface area but small contact areas with lots of air space in between. So when you have something on top of them, vibrating away, they will not transfer the vast majority of those vibrations to whatever is on the other side of the sand/shot. This is because that contact area is super small and you cannot propagate a sound wave across it because the wave is larger than the available transfer space. The added benefit is that the air in the air space between the grains/pellets needs to be compressed before it can transfer energy too. That's hard to do through just vibrations with no actual compression work being done on the air space. Add to that the stands typically not being air tight, themselves, and you will never get the air in the air spaces compressed enough to transfer enough energy to vibrate.

Foam works the same way and acoustic foam is designed specifically to have the same properties with small contact areas on the bridges between bubbles.

Given all of that, at almost 12 pounds per stand, a little bitty bookshelf speaker is not going to have the physical energy it needs to be able to vibrate the stand to resonance. Especially not at your average 50-100 watts of power for an entry level HT system. Given that it has squishy rubber feet, that further isolates it all so it doesn't transfer resonances.

On top of that, look at the size of those JBLs. PVC pipe would wiggle and vibrate like crazy because even though they are small in size compared to a floor stander, they are a healthy sized and weighted bookshelf. If the stand is not heavy/dense/strong enough to resist being vibrated by the speaker then it will end up being heavily affected by a speaker like that. Mainly because the speaker is heavier than the stand and the vibration will gain inertia which will transfer the vibrations to the flimsy stand. They gain inertia because the flimsy stand ends up acting like a spring, storing energy transferred to it until it reaches capacity and then it reacts by releasing that energy in an opposite phase to how it was transferred in to the stand. The more energy that gets cycled into and out of the stand the higher the forces get. Just like all those videos you see of suspension bridges vibrating themselves apart in an earthquake or high winds. Then not only do you get vibrations around the speaker but you also get reduce performance in the frequency response and efficiency areas because you are expending a huge amount of energy vibrating those stands and the movement of the stands is canceling out some of your low-end response because of Newton's 3rd Law of Motion.

So no, I don't think they are over-built.

steveinaz

Nice woodwork man. Great idea with the pipe---I made Bev a lamp with that stuff:

Jstas

Nice lamp!

A local bar made track lighting with black pipe and Edison bulbs like that. Looks pretty good and fits their "horse barn" decor well. (they are built on a spot where a local horse racing track once was and is no more. The spot they are on had one of the horse barns on it so they went with that theme.)

oldrocker

Nicely done..

skrol

Could bake a nice headphone stand to match the lamp and speaker stands.