When choosing a projector for a school, what should you pay attention to?

Question

Projectors

In the assembly hall of the school (large room, high ceilings, daylight) it is necessary to install a projector. In the hall, each next row is higher than the previous one. What parameters should you pay attention to first of all? There will be daylight in the room, the projector is used mainly during conferences, concerts.
Just do not give rest 2 points:
1. Sound. Now it is possible to play sound from a laptop. But since the projector will hang high, there was an idea to transmit the image over a local network, and not through VGA or HDMI. How can the sound be synchronized in this case?
2. If the projector is hanging at a height H, how much lower can the upper border of the screen be, so that the quality of the pictures does not deteriorate? The projector can be placed up to 4 meters away from the screen.

Answer 1

1. For a large room, it is not kosher to transmit sound to the projector. The speakers there are not of the power to give any acceptable voice acting. It is better to hang a few speakers on the walls, connect them to an amplifier and transmit the sound there. As for image transmission, there are converters that allow you to transmit a VGA signal (maybe HDMI exists, I haven’t seen it) over a regular category 5e UTP cable connected via RJ-45 connectors (but not Ethernet - you can’t plug it into a switch, only connect two devices directly). We have used such devices at our previous jobs and are quite satisfied with them.
2. It's hard to say. In principle, probably, all modern projectors have a keystone correction system that allows you to provide acceptable quality.
As for the parameters in general - look at the focal length and the luminous flux on the screen. It is also necessary to pay attention to the presence of a remote control for turning the projector on and off, the necessary inputs. It would be nice if the projector had some kind of lamp protection against a sudden power outage, otherwise it is recommended to install at least an additional UPS. Well, the longer the lamp life, the better. Changing a lamp is not cheap.

Answer 2

Usually the primary issue is price...

Answer 3

The main thing is to purchase equipment from a normal company https://www.delight2000.com/ as an option, otherwise, in pursuit of price, it’s not clear what. not sure where to buy