I could have sworn that I saw a post somewhere here where someone used bungee cords to solve a vibration problem, but I can't find it. It might not have been a post about vibrations.
I recall someone referring to such an approach in an offhand reference within a larger discusion. I don't recall detailed documentation of it. (This said, my recollection is sometimes as sharp as a soccer ball.)
rjlittlefield wrote: ↑Wed Feb 02, 2022 5:19 pm
At
viewtopic.php?p=236581#p236581, Chris S. reports using that approach to suspend an illuminator, to prevent its fan vibrations from coupling into the rest of the photo system.
For clarity: My illuminators are suspended from braided nylon ropes, not bungees. My first stab was a rope suspending one illuminator. This worked well, so I hung a wooden shelf from four ropes and placed three illuminators on it. This has served me faithfully for years.
For vibration reduction, I'd avoid springy things like bungee cords, and look more at "stretch and slowly return" things like braided nylon rope. For vibration reduction, we want to remove energy from the mechanical system. "Bouncy" things like bungee cords retain energy. Stretchable, but slow to return, things like braided nylon rope dissipate energy. Dissipated energy is energy that isn't hanging around to bother us.
And as Rik said, in my use, the hanging shelf's purpose is to isolate the illuminators' vibration from the camera/subject stage. Consider how energy would have to travel, to get from my illuminators to my photo system: Vibration would have to go up the ropes, across floor joists, down cinder-block walls, across a concrete floor, up a slate pool table, then into my (somewhat massive) rig. That is many degrees of decoupling (aka, lots of attenuation).
But this is very different from suspending a photo system on a hanging platform. I think such platform could work for holding a photo system. The trial and error to make it work might be, um, amusing.
The platform-on-inner-tubes approach is a classic technique. It works best with lightly inflated tubes, just barely enough to support the platform.
Classic indeed. Also the dominant approach to vibration reduction for most optic/scientific instruments: Create a platform with mass; put this platform on something squishy; let the world vibrate below, while the platform floats serenely still.
I'd avoid bicycle inner tubes--too big, unless one builds something to contain them and runs them in serpentine-fashion within this container. There are smaller inner tubes intended for go karts and wheelbarrows, which I've used.
Roller Blade inner tubes are even smaller, and look interesting. But NB: When small inner tubes are barely inflated, as they should be for this use, the valve stems stick out and can mechanically interfere with the intended use. Venture here only if you are interested in dealing with this issue.
--Chris S.