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# Comparing Two LED Signs: Quote the Matrix

Contractors know that a 2 x 4 is actually smaller than its name would indicate. The name comes from the measurement of the wood when it’s originally cut. Through the process of drying, the final measurements end up more like 1.5” x 3.5”. Still, as an industry standard consumers know what to expect.

Unfortunately, in the LED sign industry there is no uniform, standard size for sign modules. Each manufacturer has its own idea of what constitutes a module, according to size and the number of LED pixel groupings it contains. In competitive situations, it’s necessary to look beyond cabinet size and consider details like pixel pitch, matrix and viewable area in order to get a true apples-to-apples comparison.

Pixel pitch is a standard measurement that indicates the resolution of a digital sign based on the spacing of LED clusters (also known as pixels). The accepted standard is measuring from the center of one pixel to the center of the next – both vertically and horizontally. This means that an LED sign with a pixel pitch of 10mm has pixels spaced 10 millimeters apart. This is also referred to as a 10mm resolution.

The matrix of a sign is calculated by totaling the number of pixels on each module, multiplied across the entire sign. For example, a Watchfire 10mm module is 1’ by 1’ and contains 900 pixels in a 30 x 30 matrix (since there are 30 rows of pixels, which each contain 30 pixels, or 30 x 30 = 900). By taking it further, for a 10mm sign with a display area that measures 3’ x 5’, the matrix would be 90 x 150 (3’ x 30 pixels per foot, and 5’ x 30 pixels per foot). To get the number of pixels on the entire sign, just multiply 90 x 150 for a total pixel count of 13,500 in the viewable area.

Every module Watchfire makes, regardless of the pixel pitch (or resolution), measures a standard 1’ x 1’. This means we can make signs of any size in increments of one foot by one foot measurements. This also makes cabinet sizes more predictable and offers a convenient path to upgrading – particularly when the sign’s structure is grandfathered-in by strict zoning requirements. When comparing signs of similar resolutions, the best comparison comes from using the matrix of the viewing area, not the cabinet size.

Why does this matter? Smart buyers understand that many companies talk about manufacturing a “uniform” module. However, on closer inspection, you may find that the modules literally don’t measure up. Take our example above, but instead of a full 1’ x 1’ module, consider a manufacturer who plays a little loose with the measurements. Maybe the module is 10” x 10”, or even 9” x 9”. This change not only shaves off the number of pixels, but consequently reduces the overall sign matrix *and* your display area. Just like that, the viewing area is reduced by 30% and the matrix is compromised. Total pixel count for a 10mm could now be less than 9,500.

But focusing on the matrix alone won’t work when comparing dissimilar resolutions. If two signs have identical matrix numbers, but different resolutions, the sign with a larger pixel pitch will be physically larger than one with a smaller pixel pitch. A 19mm and a 12mm sign are both available with a matrix of 96 x 144, but the 19mm sign would have to be 44% larger to achieve it. The viewing area for the 12mm would be 4’ x 6’, compared to a viewing area for the 19mm of 6’ x 9’. The pixel pitch would be higher for the 12mm, and would better utilize the sign’s viewing area, particularly at close viewing distances.

Whenever possible, it’s always best to quote the matrix of a sign to get the best comparison of resolution, viewing area and cost. It’s easy to see why an inaccurate module measurement leads to lower costs. You pay less because you get less and the results will show in the size of the display, and the vibrancy and detail of the content displayed.