Refresh rate is one of those specs that every LED wall has, and you might be wondering if it matters - or not!  Different manufacturers and different models are going to have different ratings, and while you want to make sure you have a refresh rate that's "good enough", you don't want to pay for something that's overkill.

How do you know what you need?

Refresh Rate 101

The first step is understanding what refresh rate is, and why you care.  Simply put, refresh rate is how often, per second, that the media on your LED wall is updated by the video signal.  It's measured in Hz, or time per second.

There are a few key reasons why refresh rate matters.  First, having a certain refresh rate is critical for the human eye.  Slow refresh rates in any media makes images look stuttered or jumpy, especially if objects move quickly.

With LED walls, we're typically at a refresh rate of 3840hz or well above that, so the difference to the human eye is not as big of a deal as to the camera.  But the truth is, most LED walls aren't actually operating at their maximum refresh rate - as when you dim them down from 100%, you also lose refresh rate!  Because of this, you want to make sure you don't just get the minimum for your purpose - not only does going higher make your purchase more futureproof, it may be what you need today when you consider dimming your wall down (as most events will have the LED wall not running at full - especially if indoors).

Cameras and Shutter Type

To understand why you may need a high refresh rate, it's important to know cameras work, and interact with your LED wall.  As we always say - even if you don't have cameras in your event, the people in the audience will get out their phones and take photos/video (even if prohibited!), and you want those photos/video to look as good as they can.

Cameras work in one of 2 ways as they capture images.  Every camera has a shutter speed, or the rate per second that they take individual frames to make up a video - no matter if it's a phone camera, a cinema camera, or anything in between.

How they capture that image at 24 to 120+ frames per second varies.  Many cameras are CMOS cameras - where in that 1/60 of a second, for example, the camera is capturing pixels 1 by 1 within that time.  Other cameras have a global shutter, which captures the entire frame in one instant.  This is a BIG difference when it comes to LED walls.

CMOS cameras can suffer from "roll", where you see bars running on the screen, or even a section of LED wall that is darker or lighter than the rest on camera, but not in real life.  Sometimes, changing the framerate slower or faster can help resolve the problem, but in a lower-quality LED wall, you may not be able to get rid of it.

This is because CMOS cameras are constantly scanning across and down their sensors, gathering each frame over time.  It all happens quickly, but the difference in when the parts of the frame are captured can and will cause issues with LED walls that do not have high enough refresh rates.

Why? Because LED walls are doing a similar process to CMOS cameras, where they are refreshing smaller segments of the wall constantly - they are not refreshing the entire screen at the same time!

This is why almost universally, LED wall vendors recommend at least a 3840hz refresh rate, if not higher.  Going higher will never hurt you and will make the useable life of your LED wall longer as technology progresses and higher refresh rates become standard.  Of course, you don't want to overpay for a feature you don't need, so it's a balance.

If you are shooting high framerate/VR type work, you want to be at 7680hz or greater to ensure camera tracking works properly.  If not, it doesn't hurt if the cost is similar or not a great deal more.

The short version - refresh rates matter, and if your LED wall vendor doesn't provide full specs including refresh rate, you should find a new LED wall vendor.

Where Do You Go Next? 

Whether you're looking to do high-speed VR work, or just need a LED wall for side screens or besides your stage, we're here to help at Above AVL. 

When you're looking for an LED wall, it's very important to get a proven LED wall from a manufacturer who will provide a quality product on day 1, and provide support for years. 

That's why we work with multiple brands of LED to find the perfect match of LED wall for your needs - bringing into consideration how you will use your wall and what features are important to you - so that you get a wall that will last the long haul and serve you well. Use our LED wall calculator to get started!