By their usage the viewing distance is depending on their individual makings (pixel pitch). This means that we need minimum 5 to 25 meters between the LED wall and the auditorium to see the picture clear. 
Basic rule: the minimum viewing distance in terms of meters equals with the pixel pitch of the LED wall in a terms of mm.

Because of the different size, function and field of usage LED walls represents different price category than indoor projectors.
There are several type of LED techniques exist. We categorized them below in out-and indoor and “mobile” groups and furthermore we divided the indoor LED walls in to ordinary and LED frame (decorating LED wall) category.

LED walls - modular - IN- and OUTDOOR

LED walls consists of modules, on these modules the pixels are created of high brightness LEDs.    

The modules can be combined differently, individually (LED wall, LED banner, column, etc.)
The input signal can be: video or PC signal.
Input signal sources: camera, video casette player, DVD, satelite or TV antenna, or any other video signal, PC signal.