LAN Comms

I was wondering how comms are handled at LAN events. I figure it's hardware somehow but if anyone knows how it would be set up I'd appreciate it if you could let me know how it's done. I'm trying to look into a solution for my college's esports team at practices and matches as we all use discord but when we're in the same room we experience latancy.

they just yell really loud at eachother, rito too cheap for teamspeak