Pitch is a resolution decision disguised as a product name
A 2.5 mm cabinet and a 3.9 mm cabinet of the same physical size are the same box on the truck and very different screens. A 500 mm cabinet at 2.5 mm pitch holds 200 by 200 pixels. The same cabinet at 3.9 mm holds 128 by 128. Build a ten-by-six wall out of each and you get 2,000 by 1,200 in the first case and 1,280 by 768 in the second — from HD-and-a-bit down to something that cannot show a full HD frame without throwing pixels away.
That is the real cost of a coarser pitch, and it shows up as soft text long before anyone notices individual LEDs. The usual guide of about one metre of viewing distance per millimetre of pitch is a reasonable place to start for whether the emitters separate visually, but the resolution question bites first for any content with type in it.
Worth checking on any spec sheet: cabinet width divided by pitch has to be a whole number of pixels. If it is not, the pitch in the product name has been rounded. A 500 mm cabinet described as 2.6 mm is usually 192 pixels at 2.604 mm, and the difference matters when you are working out how many pixels the processor has to feed.
The wall is rarely the shape of the content
Cabinets come in whole units, so the wall comes in whole units, and whole units almost never land on 16:9. Ten by six 500 mm cabinets gives 5 by 3 metres, which is 1.667 to 1, against 1.778 for HD. Fit an HD frame inside that and it fills the width and leaves 75 pixels of black across the bottom, or the top, or split between them. Nothing is wrong; the shapes simply differ.
There are three ways out and only one of them is good. Stretching the source to fill distorts everything and is visible on any circle or face. Cropping fills the wall and throws away the top and bottom of the frame, which is fine for a camera feed with headroom and fatal for a lower third. Building the content at the native resolution of the wall costs design time and looks right, and it is what any wall of an unusual shape ends up requiring. Working the pixel dimensions out before the content is designed rather than after is the entire trick.
Weight adds up faster than the picture does
Sixty cabinets at 15 pounds is 900 pounds of panel, and that is the smallest number in the rigging conversation. A hung wall carries a header bar or truss, a frame, cable, power and data looms, sometimes a processor, and a set of spare cabinets that live on the floor. The distributed figure is not what a rigger works with either; the load arrives at discrete hanging points, and the spacing of those points is what the arithmetic has to be about.
Ground-supported walls trade the rigging question for a footprint and a ballast question, and both of those depend on where the wall is and what the wind can get at. Outdoors, a wall is a sail. None of that is arithmetic that belongs on a calculator page, and all of it belongs with a qualified rigger and, at any size, an engineer.
Power, and the slide that trips the breaker
Manufacturers quote two draw figures because the gap between them is enormous. Ordinary video content sits somewhere near the average, since most frames are nowhere near all-white at full brightness. A full-white test pattern, a title card, or a brightly lit camera feed of a white backdrop pushes towards the peak, and peak can be two or three times average. The failure mode is memorable: the wall runs all day on rehearsal footage and trips during the opening slide.
Size the distribution on the peak. The inrush when a large wall powers on is its own consideration, which is why big walls get switched on in sections rather than all at once. The event power distribution calculator splits a load list across circuits and gives the generator figure; the AV rack power and heat calculator covers the processing end, which also has to go somewhere and also makes heat.
If the wall is replacing a projector rather than joining one, the projector throw distance calculator is the comparison — the trade is essentially ambient light tolerance and installed cost against throw distance and a dark room.
Questions people ask
How do I calculate the resolution of an LED wall?
Divide the cabinet width by the pixel pitch to get pixels per cabinet, then multiply by the number of cabinets across. Do the same vertically. A 500 mm cabinet at 2.5 mm pitch is 200 pixels wide, so ten across is 2,000 pixels. It is worth sanity-checking that the division comes out whole, because a pitch quoted in a product name is often rounded and the true figure is whatever gives a whole pixel count.
What pixel pitch do I need?
It depends on how close the nearest person gets and what the content is. The common starting guide is roughly one metre of viewing distance per millimetre of pitch, so 2.5 mm suits an audience two and a half metres back and further. But resolution usually decides it before visible pixels do: a coarse pitch on a small wall may not have enough pixels to show an HD frame at all, and text is where that becomes obvious. Work out the pixel count first, then check the viewing distance.
Why does my content have black bars on the LED wall?
Because the wall is not the same shape as the source. Cabinets come in whole units so the wall lands on whatever ratio the grid produces, which is rarely 16:9. Fitting a standard frame inside a differently-shaped wall leaves bars on two sides. Stretching distorts, cropping loses content, and the clean answer is designing the content at the native pixel dimensions of the wall — which means working those dimensions out before the design starts.
How much power does an LED wall use?
Two numbers, and both come from the manufacturer: an average figure for ordinary content and a peak figure for all pixels white at full brightness. The peak can be two to three times the average. Distribution has to be sized on the peak, because the moment that draws it is a white title card rather than anything exotic, and a wall that has behaved all day will trip on it. Powering a large wall up in sections rather than all at once is standard practice for the inrush.
How much does an LED wall weigh?
Panel weight is cabinet count times the spec sheet figure, and it is the beginning of the number rather than the end. The header, frame, cable looms, power and data distribution and any spare panels all add. More importantly, a rigger does not work with the total: the load arrives at discrete hanging points and the spacing of those points is the question. Whether a structure can take it is for a qualified rigger and an engineer, not for a calculator.