You would need to have an entertainment
truss welder's certifications as seperate than even welder's certificates and X-Rayed welds on the manufacturer
level, much less engineering and loading certificates about a
truss system - including size and weight of
base. Or the question of even leverage dependant upon weight of
fixture, it's distance from the
ground and how far out it is as factoring into the
base support in question even if only a tower.
In the case of the
speaker stands, the speakers are perched in a balanced position above the stands. Force is only in a downward direction with only a little built in for sway brace since it's not out of balance. Attempt to use them as a
boom, it depends upon the combination of weight and
leg length for overall stability of the top heavy speakers as to how far out of balance you are now safe in throwing them off.
Walk across the carpet in your room adjacent to the
speaker and it could make it fall over. On the other
hand, it could be just fine. (
Safety cabling booms and when possible stands to the roof or wall is always a wise tactic.) Might recommend hanging the
fixture directly over one of the legs, but also remember that the stand is engineered to support a weight above it only on the same axis plane perpendicular to the floor. Clamping pressure on something only meant to be strong
in one dimension could be like crushing a coke can.
Try the famous experiment. Stand on an empty coke can than have someone just touch the side of the can under you.
This is a similar reason to why a
truss that is radio tower when used in a different axis might not be very strong even if still a
truss.
Lumber - avoid it if possible for something perminant and not covered by flame resistant materials or for lighting equipment.
Welding your own, depends - but only in a professional setting with a certified welder authorized by the school to weld.
In the end, I like Len's idea but might take it one step further. Once you present your need for the lighting position, and you sheepishly pose your option for it to be rejected, you bring a price quote out of your pocket - that is now much more reasonable in cost to have done given the problem presented and it as the best way to get done. Price must be reasonable in symplicity.
Just a question than of to what extent you want this done. Could be as simple as a pipe with various forged steel (not malleable or cast) elbows and parts bolted to the wall. Simple C-Shape say out from the wall by 12", neat and less obtrusive than some lumber tower. Could be a professional
truss stand but it than can be tripped over by the audience. Could be a pipe running floor to ceiling that's using again forged or designed for such stress and loading parts to mount and couple it. If nothing else, a 40#
boom base, a pipe and have a certified welder weld a chain link to a pipe cap. This or drill it for a
drop forged eye
bolt. Than
wire rope off to the ceiling.
Problem with
stage weights or sand bags in other than a temporary situation is both because it adds height to what you don't want someone to be
tripping on, and they are not a perminant - other than most often in a hack way solution to your problem. What happens when the sand bag gets a hole or someone needs a door stop? Your temporary fix for adding weight is than very temporary and dangerous.
Keep thinking, care is good, just a question of time in having experienced solutions and learning about enough options at times before you do come up with a solution. Asking here and everywhere and anyone you can is also good.