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Midway has an excellent selection. You might obtain better results with copper clad lead shot than pure lead, or the tungsten shot (Hevi-Shot) is as dense as lead and harder than steel. Pure lead has been accused of having a dull blur. I think lead is OK in some applications, it isn't good for the delicate micro vibes though. Tried bags of straight lead on top of my speakers and wasn't impressed, added an strange "brown" quality, as in micro contamination with brownian motion. I think this is specific to the way that lead balls store and release energy. Lead pieces may not be as brownian. I'm getting some good initial sense of Hevi-Shot, comes in 7 lb. jars. if you drop a Hevi-Shot on to a piece of steel, instead of bouncing it goes kerplunk and sits there where a hard bearing would be dancing all over creation. Let's see if this link works.
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I use copper coated BBs. About $7/pint. One pint or more per stand in bottom. Then fill with sand to fill in gaps in bottom and up to top. Idea is to keep center of mass/gravity very low for stability, but to ensure no gaps in fill/damping against metal legs. I do NOT do it to increase bass, but it does impact it that way....
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for use in filling rack tubing?I will be doing this shortly, and sand is not an option for me.
Also, can the shot be coated with something like polyurethane? If so, would this help?
Thanks for the info.
Unless you need to lower the center of gravity, simply adding mass with heavier materials is not a good idea. The rack frame members have a resonant spectrum determined by their mass and stiffness. When you add a filler, you provide some damping but you also increase the mass of the total structure without increasing the stiffness.The result is the resonant spectrum is shifted down. Even with the added damping, the total motion may be increased because of this shift. This may make the audio consequences worse instead of better.
You might want to consider using a lighter filling material. I like clay oil absorber, that looks like kitty litter, because it couples well to rack frame metal, but is lighter than sand. Polyester batting is very light indeed, but does not couple well to steel rack tubes in my experience, even if firmly packed into them. Polyurethane construction adhesive (less than $3 per tube in the big-box home improvement stores) dries to an acoustically dead hard rubber. If you could contrive to simply coat the insides of your rack frame tubes with this stuff, it might work better than any passive filling. In any case, it is good for caulking the joints where the dust from the filler might leak out.
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I need to experiment with this. According to the Star Sound people, they tried every bearing metal in the world before settling on this specific steel and specific diameter. The one drawback is that it is ferromagnetic.
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these guys could probably cook up an awesome rig for you
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