The scan line problem
An LED wall is not lit all at once. Each row of modules is refreshed in sequence, thousands of times per second. A camera with a rolling shutter reads one line at a time, so if the refresh rate and the shutter timing do not line up, the camera catches the wall in the middle of a refresh. That is the dark band.
What the numbers mean
| Refresh rate | Works with | Risk |
|---|---|---|
| 1920 Hz | Human eye, stills | Visible banding on phone video at 1/1000 s |
| 2880 Hz | Most consumer cameras | Banding at very fast shutter |
| 3840 Hz | Broadcast, event filming | Low risk up to 1/2000 s |
The test that settles it
Do not accept a number on a datasheet. Ask for a video file: the wall showing a white slide, filmed at 1/1000 s shutter, 60 fps, with the camera moving slowly across the wall. If there is a band, you will see it in three seconds. Any supplier with real 3840 Hz product will send that clip without arguing.
Where it matters and where it does not
A lobby wall that will never be filmed: 1920 Hz is fine, and the price difference is real. A conference centre, a church, a stadium, or any venue where guests will post phone video: pay for 3840 Hz. The cost of a screen that bands on every phone video is much higher than the refresh rate upgrade.
A related trap
Refresh rate is not the same as frame rate. A controller outputting 60 Hz to a 3840 Hz wall is still 60 frames per second; the 3840 refers to how fast each row is re-scanned. Sales sheets sometimes blur the two. Ask for both numbers separately.