The arithmetic, so you can see there is nothing hidden in it
Two supports, a rigid beam, everything vertical. Take moments about the left pick: every load contributes its weight times its distance past that pick, and the truss weight contributes its total acting at its own midpoint. Divide the sum by the distance between the picks and you have the load at the right pick. Subtract that from the total and you have the left. There is no third equation and no coefficient — it is one division and one subtraction, which is why the answer is exact for the model and why the model is the thing worth arguing about.
Work the default through. Six loads totalling 405 pounds, a 32 foot truss at 4 pounds per foot for another 128, so 533 pounds in all. Moments about the pick at 2 feet come to 6,502 foot-pounds, the picks are 28 feet apart, so the right pick takes 232 pounds and the left takes the remaining 301. The centre of gravity lands at 14.2 feet from the left end, left of the midpoint of the picks, which is exactly why the left pick has more of it.
Notice what moving a single fixture does. Slide the 120 pound speaker from 8 feet to 24 feet and the right pick goes up by nearly 70 pounds while the left comes down by the same. Load moves between picks in proportion to how far along the span it sits, and a heavy item near one end is almost entirely that end problem.
Overhangs are not free and not intuitive
Picks are rarely at the very ends. Bringing them inboard shortens the span, which people like, and creates cantilevers at both ends, which they think about less. A load out on an overhang still has to be carried, and it is carried by levering against the near pick — which means the near pick takes more than the load and the far pick takes less. Far enough out and the far pick reaction can go negative, meaning that end wants to lift rather than hang.
The arithmetic here handles overhangs correctly because taking moments does not care which side of the pick a load sits on. What it does not do is warn you about it, because there is no threshold to warn against that would not be a capacity judgement.
What is deliberately not here
No verdict. Not a pass, not a fail, not a percentage of anything, not a colour. That is not caution for its own sake — it is that a truss capacity figure is meaningless without the context it was published in. A manufacturer load chart gives an allowable load for a specific section, at a specific span, under a specific loading pattern (uniformly distributed is not the same as a single centre point load, which is not the same as four evenly spaced points), with specific end connections and specific bracing. Reading a number off one row of that chart and applying it to a different arrangement is the error the chart is designed to prevent, and a calculator that did the comparison for you would be encouraging exactly that.
Deflection is absent for the same reason and one more: a truss can be well within its allowable load and still sag enough to be a problem for a projection surface, a header, or anything that has to stay straight. That calculation needs the section stiffness, and stiffness is a property of the specific product.
Also absent: anything about the hardware. Hoists, chain, slings, shackles, couplers and the structure above them each have their own ratings and their own failure modes, and the load at the pick is only the first of several numbers that have to be checked against several different documents.
Where the real answer comes from
A qualified rigger, working from the manufacturer load chart for the exact section in front of them, and an engineer for the structure the whole thing hangs from. In most jurisdictions rigging over occupied space is regulated work, and venues that host it have their own requirements about who may do it and what has to be shown to them beforehand. The point of a page like this is to get a hang plot into numbers early enough that the conversation with those people is a short one, not to replace it.
Two neighbouring calculations, both of which stop at the same line: the LED video wall calculator gives you the panel weight that ends up here, and the stage deck layout calculator handles the version of this problem that sits on the floor instead of over it.
Questions people ask
How do I work out the load on each end of a truss?
Take moments about one support. Add up each load multiplied by its distance from that support, include the truss weight acting at its own midpoint, and divide the total by the distance between the two supports — that gives the reaction at the far support. Subtract it from the total weight for the near one. Loads near a support are carried almost entirely by that support; loads at the middle split evenly.
Can this tell me if my truss can take the load?
No, and that is not a limitation that could be fixed with more inputs. An allowable load figure belongs to a specific truss section at a specific span under a specific loading pattern with specific end conditions, and those come from the manufacturer load chart rather than from any general formula. Beyond the truss itself there are the hoists, the slings, the shackles, the couplers and the structure it hangs from, each with its own rating. The answer comes from a qualified rigger and, for the structure, an engineer.
What does the centre of gravity of a hang tell me?
Where the weight really is, which is often not where it looks. If the centre of gravity sits away from the midpoint between the picks, the nearer pick is taking more, and the further it drifts the more lopsided that gets. It is the single most useful number for spotting a hang plot that has quietly become end-heavy, and it is also what determines how the bar behaves when it is being lifted on two hoists that are not perfectly matched.
Does it matter where the pick points are?
A great deal. Moving picks inboard shortens the span between them and creates cantilevers at the ends, and load out on a cantilever levers against the nearer pick — that pick then takes more than the load itself while the far one takes less. Far enough out and the far reaction can turn negative, meaning the end wants to lift. The arithmetic handles all of that, but where picks may go is a rigging decision constrained by the truss design and the structure above.
Is a distributed load the same as point loads that add up to the same weight?
Not for the truss, though the reactions come out the same. Two supports carrying 500 pounds see 500 pounds either way, so this page gives the same reactions. Inside the truss the two cases are quite different, which is precisely why manufacturer load charts publish separate columns for uniformly distributed load, a single centre point load, and evenly spaced point loads. Using the distributed figure to justify a single heavy point in the middle is one of the classic ways a chart gets misread.